Three’s Company Star Joyce DeWitt Steps Out in Support of Late Costar John Ritter at His Charity Event

Joyce DeWitt is keeping the legacy of her late Three's Company costar John Ritter alive.

The actress, 75, was all smiles as she posed on the purple carpet at An Evening from the Heart, a gala presented by The John Ritter Foundation for Aortic Health on Thursday, May 9 at Sunset Room Hollywood in Los Angeles.

DeWitt was fashioned in a black pants suit with black and white polka dot details adorning the buttons on her jacket and the lining of her cuffs. She paired her look with silver and pearl-like jewelry and blue nail polish.

As fans may know, DeWitt starred on Three's Company alongside Ritter from 1977-1984. She played Janet Wood while Ritter played her roommate Jack Tripper for all eight seasons. The pair were also joined by Suzanne Somers, who played third roommate Chrissy Snow.

Thursday's event celebrated the life and legacy of Ritter, who died in 2003 at the age of 54 of a "misdiagnosed acute aortic dissection," according to the foundation's website.

At the time, PEOPLE reported that the Emmy-award winning actor died after he collapsed on set of his ABC comedy 8 Simple Rules. He was taken to Providence St. Joseph Hospital in Burbank, California, but surgeons there were unable to save him.

“All of us at ABC, Touchstone Television and the Walt Disney Company are shocked and heartbroken at the terrible news of John’s passing. Our thoughts and prayers are with his wife and children at this very difficult time,” ABC wrote in a statement shortly after the news.

“It’s just stunning, unbelievable,” Susan Wilcox, his assistant of 22 years, told the Associated Press at the time. “Everybody loved John Ritter. Everybody loved working with him. … Whatever set he was working on, he made it a very fun place.”

DeWitt wasn't the only one of Ritter's former costars to attend the event. Kaley Cuoco also showed her support for the cause. The actress, who starred on 8 Simple Rules with Ritter, was seen dressed to the nines in a silver floor-length sequined dress with flowy sleeves.

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"He touched a lot of lives," Cuoco told PEOPLE in an exclusive interview at the event.

Cuoco said she became very close to Ritter's family, who has "worked very hard" for the past two decades to bring awareness to aortic dissection.

"I will do anything for his wife and his kids," she continued. "And I'm so really very proud to be here and honoring him."