Erin Foster Celebrates Halloween with Mom Rebecca and Soon-to-Be Stepmom Katharine McPhee

"Love my two moms," joked Foster on social media

By Tomás Mier
Published on November 2, 2018 06:39PM EDT

Just fostering love!

Erin Foster couldn’t be happier to have (almost) two moms. The Barely Famous star, 36, shared a photo on Friday from a Halloween bash posing with her father David Foster‘s fiancée Katharine McPhee and her mom Rebecca Dyer.

“Love my two moms ❤️,” Erin captioned the photo of herself with Dyer and McPhee, 34, who got engaged to David Foster this summer. Dyer — Erin and sister Sara Foster‘s mother — was married to David from 1982 to 1986.

The “Terrified” singer sported whiskers and Minnie Mouse ears for the party while Erin wore a skeleton-print sweater.

The photo comes a day after McPhee and David celebrated his 69th birthday with lots of PDA both at lunch and at the Friends of the Israel Defense Forces (FIDF) Western Region Gala on Thursday.

Katharine McPhee and David Foster Open Up About Their Love
Friends of the Israel Defense Forces western regional gala, Los Angeles, USA - 01 Nov 2018
Rob Latour/Variety/REX/Shutterstock

In August, Erin jokingly commented, “FEELS LIKE I COULD HAVE BEEN INVITED ON THIS BEAUTIFUL TRIP” on a photo of McPhee while she was on vacation with the musician. “Mommy and daddy need alone time,” McPhee responded.

Sealed with a Kiss! Katharine McPhee and David Foster Show Plenty of PDA at Beverly Hills Gala

The couple opened up to PEOPLE about their journey to love in September. “We genuinely love and respect each other and have for a very long time,” McPhee told PEOPLE.

“She didn’t catch my eye on the first day because I was so busy trying to do my job,” added David. “But the reality is that in the last 12 years I’ve always had a connection with her.”