Three of David Foster's daughters have opened up about the "biggest issue" they have with his fifth wife Katharine McPhee, and it has nothing to do with the couple's 34-year age gap. In this week's issue of People, 39-year-old Sara, 37-year-old Erin, and 33-year-old Jordan Foster talked about their dad's wife, who at 36 years old is younger than both Sara and Erin and only one year older than Jordan.
The ladies, who David shares with ex-wife Rebecca Dyer, got candid about David and Katharine's relationship in a new interview with their dad, where they confessed that they don't like how the American Idol Season 5 runner-up is in such amazing shape.
"Our biggest issue with [Katharine] is how hot she is," Erin admitted of the former Smash star, who is also stepmom to David's other daughters, 50-year-old Allison and 46-year-old Amy, from previous relationships.
"Her body is insane. When she comes over for family Sundays, I'm like, 'Do not get in a bikini,'" she quipped, joking that her husband Simon Tikhman often tries to convince the "Over It" singer to get into a two-piece while the family is hanging out.
"My husband's always like, 'Kat, get in the pool!' And I'm like, 'Simon...'" she said.
Sara added that all of their husbands "hang on the side ogling [Katharine]," while Jordan joked that even her 2-year-old son Otto has eyes for the star.
As well as joking about her smoking bikini body, the trio also opened up about the age gap between Katharine and her 70-year-old husband.
Erin admitted that the over three-decade age difference between them has actually been a positive thing because Katharine has taught David how to "open up" more with his family members.
"We could get into a fight, and then Kat's like, 'No, you have to pick up the phone, call your daughter back.' She's a facilitator, which is really important. She pushes him to be more emotional and more vulnerable," she said.
David also spoke to the outlet about how Katharine has taken on the role of stepmom to all of his children, four of which are older than her. He admitted that all the women in his life have adapted "really well" to their age gap relationship, which has raised a few eyebrows since they were first romantically linked in 2017.
"They could be horrible. It sure makes it easier for me that they get along," he said, adding that they've all been on good terms for years now.
Katharine and David married last year in London after they became engaged in June 2018, around a year after they started dating.
The latest family chatter about Katharine and David's relationship came shortly after the former joked about the "real reason" she married the musician on Twitter earlier this week.