David Harbour and Lily Allen's Relationship Timeline

David Harbour and Lily Allen can't help but "smile" whenever they're together.

After sparking romance rumors in 2019, the Stranger Things actor and singer tied the knot during a Las Vegas wedding in September 2020. In addition to having an Elvis impersonator officiate the ceremony, the couple was joined by Allen's two children, Marnie Rose and Ethel Mary, whom she shares with her ex-husband Sam Cooper.

Since officially becoming husband and wife, the two have continued to give us sweet glimpses of their romance, including attending red carpets together and speaking highly of each other during interviews.

"I'm so grateful that I'm not alone anymore, and that I have someone that I can tell everything to and who can tell me everything," Harbour told PEOPLE about Allen in 2021.

"We can share this experience of walking through life together," he continues. "I'm always so overcome with gratitude for that, because I've been alone for most of my life."

Take a look back at the couple's relationship timeline ahead.

Jan. 5, 2019: David Harbour and Lily Allen attend the BAFTA Tea Party together

The two were first linked in January 2019, when they attended the BAFTA Tea Party together. The appearance came shortly after Allen revealed that she had split from DJ Meridian Dan, who she had been dating since 2015.

August 2019: David Harbour and Lily Allen step out in London as he films Black Widow

Allen and Harbour were spotted together again in August 2019 while he was filming Black Widow in London. While in England, the two also attended a performance of The Lehman Trilogy together, according to E! News.

Oct. 12, 2019: David Harbour and Lily Allen attend an SNL afterparty together

Following Harbour's Saturday Night Live hosting gig on Oct. 12, the actor was spotted attending an afterparty with Allen in N.Y.C. Harbour's father, Kenneth, was also photographed with the pair heading to the party.

Oct. 12, 2019: Lily Allen seemingly confirms David Harbour dating rumors

Shortly after Harbour hosted SNL, Allen seemingly confirmed their relationship when she shared photos from Harbour's SNL sketch parodying a SoulCycle class, during which he wore a sleeveless shirt and showed off his muscular arms. In a zoomed-in photo of Harbour's bicep, Allen captioned her image: "Mine."

Oct. 13, 2019: David Harbour and Lily Allen share a kiss in N.Y.C.

On Oct. 13, the two kept the appearances in the Big Apple coming as they were photographed sharing a kiss as they grabbed lunch together.

Oct. 17, 2019: David Harbour and Lily Allen attend their first red carpet as a couple

After the public PDA, the two made their first red carpet appearance as a couple as they attended The Skin Cancer Foundation's Champions for Change Gala at the Plaza Hotel on Oct. 17.

Oct. 18, 2019: David Harbour and Lily Allen attend a New York Knicks game

The following day, Harbour and Allen caught a basketball game at Madison Square Garden as they watched the New York Knicks take on the New Orleans Pelicans. While sitting courtside, the couple shared a kiss for the cameras.

Oct. 28, 2019: David Harbour and Lily Allen go Instagram official

On Oct. 28, Harbour made his relationship with Allen Instagram official when he posted a photo of them enjoying a day at Disney's Magic Kingdom in Florida. "The prince, princess and the parking lot," he captioned the mirror selfie of the pair, in which Allen's face is turned away from the camera. "That seven dwarves mine ride is the best one in the whole damn park. Go on, fight me. #magic #disney #rulebreakers."

November 2019: David Harbour opens up about Lily Allen in PEOPLE's Sexiest Man Alive issue

Speaking with PEOPLE for the Sexiest Man Alive 2019 issue, Harbour, who was named one of the Men of the Year, revealed that Allen gave him one of the best non-work-related compliments he's ever received.

"Lily Allen once told me that I was so gorgeous it was an outrage," he said. He added that he feels the same way about Allen, saying, "I really only look at my girlfriend's eyes, until she's turned away from me and I stare at her stunningly beautiful butt."

November 2019: David Harbour and Lily Allen spark engagement rumors

In November 2019, the couple sparked engagement rumors after Allen was spotted wearing a ring on her left finger, though the two didn't address the rumors at the time.

Jan. 19, 2020: David Harbour and Lily Allen attend the SAG Awards together

During the 2020 SAG Awards, Harbour had Allen by his side as he was nominated for outstanding performance by a male actor in a drama series for his role on Stranger Things. In addition to walking the red carpet together, Harbour also posted about their date night on his Instagram, calling Allen "brilliant, beautiful, brash, bold, brave and just f—ing hot" as she sported a red dress.

April 10, 2020: Lily Allen throws David Harbour a birthday party at home

In celebration of Harbour's 45th birthday on April 10, Allen threw him a party at home amid the coronavirus pandemic. In a collage shared on his Instagram, Harbour showed off pictures of his at-home celebration which included colorful decorations, flowers, a homemade birthday cake, and cupcakes.

Sept. 7, 2020: David Harbour and Lily Allen get married in Las Vegas

On Sept. 7, Harbour and Allen tied the knot in a Las Vegas wedding officiated by an Elvis Presley impersonator and followed by a meal of In-N-Out burgers.

"In a wedding officiated by the king himself, the people's princess wed her devoted, low born, but kind credit card holder in a beautiful ceremony lit by the ashen skies courtesy of a burning state miles away in the midst of a global pandemic," Harbour captioned his post.

October 2020: Lily Allen says she wants kids with David Harbour

In an interview with The Sunday Times, the British singer and mother of two opened up about wanting to have kids with Harbour following their wedding.

"I think so. Especially now Marnie's getting so big," Allen said when asked about expanding her family. "It's like, 'No, my babies!' " However, Allen said she's likely waiting a few years before she gets pregnant again. "I'm in a really good place. I don't know if I'd mess with my hormones, at this particular point," she said.

December 2020: David Harbour opens up about married life to Lily Allen

While talking with PEOPLE, Harbour praised his wife following their recent nuptials. "I married a beautiful, incredible woman who I love," he said. "I have never met someone who is so deeply kind as her. I've never felt so taken care of and cared for by another human being. She really is just a deeply kind individual and I love that about her."

June 2, 2021: David Harbour says Lily Allen's daughters inspired him to marry her

During an appearance on Jimmy Kimmel Live!, Harbour opened up how a conversation with Allen's daughters when they were riding bikes led him to get married to Allen.

"The little one was riding along and she was going like, 'David, dad, David, dad.' Because the D got her confused," he recalled to the host. "And the older one got very upset with that, which I understand. She was like, 'He's not our dad! He's not our dad!' "

Harbour continued: "And then younger one was like, 'Well what is he? He's kind of our dad.' She's like, 'No he's not, he's our stepdad.' And she goes, 'What is he?' And she goes, 'He's just some guy in our lives!' "

The actor admitted that the conversation confirmed it was time for him to take the next step. "I was like, 'I need to marry this woman,' " Harbour joked. "Because the emotional fallout ... "

July 2021: David Harbour says he's "grateful" for Lily Allen

While speaking with PEOPLE in July 2021, Harbour opened up about how he was so "grateful" to have Allen in his life. "I'm so grateful that I'm not alone anymore, and that I have someone that I can tell everything to and who can tell me everything," he said. "We can share this experience of walking through life together. I'm always so overcome with gratitude for that, because I've been alone for most of my life."

Sept. 8, 2021: David Harbour and Lily Allen celebrate their first wedding anniversary

In September 2021, Allen celebrated her first wedding anniversary with Harbour by sharing a carousel of photos and videos on Instagram. "1 year down with this guy. Happy Anniversary baby @dkharbour," she wrote. "I prefer my life with you in it. You can stay. 😘"

April 20, 2022: David Harbour and Lily Allen hold hands at the Olivier Awards

On April 20, Harbour and Allen attended the Oliver Awards at Royal Albert Hall in London. The duo was spotted holding hands as they made their way down the red carpet.

May 2, 2022: David Harbour and Lily Allen attend their first Met Gala together

On May 2, the two attended the 2022 Met Gala, which marked Harbour's first time at the event and Allen's second time at the event after previously attending in 2014.

May 14, 2022: David Harbour and Lily Allen attend the Stranger Things season 4 premiere with their family

Harbour was accompanied by Allen and her kids as they attended the Stranger Things season 4 premiere in Brooklyn, New York on May 14.

June 2022: David Harbour talks about falling for Lily Allen

In a new interview with GQ Hype, the actor talked about falling for Allen after meeting on a dating app. "I was in London alone, doing Black Widow, on this app, going on dates and stuff. And yeah, I started texting with her," the actor recalled.

"She was in Italy at the time – we got together, went on a date at the Wolseley [a restaurant in Mayfair], and it was, you know, she's f------ unbelievable," he continued.

He noted that while Allen says it was love at first sight for her, Harbour really fell for her on their third date. "I remember the exact moment. It was our third date," he said. "I was just in this phase, where I was like, I'm just going to be brutally honest about everything, because why lie? And I told her something about my life, about my beliefs… It would take a really extraordinary person to be accepting of the things that I said. And I remember thinking: Wow, that's somebody I want to be around."

September 7, 2022: Lily Allen and David Harbour celebrate their second wedding anniversary

Allen and Harbour are going strong two years after tying the knot in Vegas.

"Happy Anniversary @dkharbour. Love ya ❤️," the singer captioned a photo of the couple on Instagram.

November 30, 2022: David Harbour and Lily Allen attend the premiere of his film Violent Night in Los Angeles

Harbour plays Santa Claus in the Christmas-themed film Violent Night. At the movie's premiere in L.A., The Stranger Things star, who donned a black suit and a red pocket square, was joined by Allen on the red carpet. The fashionista wowed in a sparkly, button-down coat dress.

"HO HO HOLY *%#%# the @violentnight premiere was a blast! See it in a crowded theater ❤️🎅🎄," Harbour wrote on Instagram.

February 1, 2023: David Harbour and Lily Allen give Architectural Digest a tour of their home

Harbour and Allen reside in a townhouse in Brooklyn, New York, which was designed by Billy Cotton in collaboration with the actor and songstress.

In the couple's interview with AD, Allen describes their home as "weird and wonderful."

To which Harbour said, "Lily is someone who lives with color in a deeper way than most. Her taste is bold, silly, fun, eccentric—it's exciting. She has such presence and star quality, you just can't picture her living somewhere boring and conventional."

Meanwhile, the couple's two daughters call the colorful and eclectic brownstone "the clown house."

"But they say it in the most loving way," Allen added.

September 7, 2023: Lily Allen celebrates her 3-year anniversary with David Harbour

In September, Allen posted a throwback to her and Harbour's wedding in honor of their three-year anniversary. "3 years with this guy," she wrote alongside a photo of her smiling at Harbour. "2nd best decision I ever made. 1st was that dress."

December 2023: Lily Allen and David Harbour spend Christmas together in India

On Dec. 26, 2023, Allen shared photos from the couple's trip to India over the Christmas holiday in an Instagram post. In the photos, Allen and Harbour sipped drinks while on an excursion and posed for a silly selfie, and the singer also shared a peek at some of the shops and markets they'd visited during their trip.