After attending the same school together as teens, McPhee and the Duchess of Sussex reconnected last year — and now their husbands share a close bond.
"My husband has a really, really beautiful relationship with Harry," McPhee told Access Hollywood. "They're like, they’re so cute. They're like father and son."
"We just stay in touch with them," the actress and singer continued. "But mostly, Meghan and I knew each other from childhood, but really Harry and my husband are friends. It's really nice."
Foster revealed earlier this year that he arranged for the royal couple — and son Archie, who just celebrated his first birthday — to stay at a mansion on Vancouver Island in Canada owned by a close friend.
"I felt honored that I was able to help Meghan there, because I’m a Canadian and we’re a commonwealth country, we’re the Crown's. It’s important to us, so I grew up with that kind of sentiment,” the music producer told the Daily Mail in January. “I was really happy to be able to help them to find a respite just to take a little time off."
Samir Hussein/WireImage Archie, Meghan Markle and Prince Harry
"I had very little to do with that," McPhee told Access Hollywood. "David's the resource guy. He loves to help people."
Meghan and Prince Harry have since relocated to Los Angeles, Meghan's hometown, but McPhee says she and her husband "just want them to end up wherever they feel safest and happiest."
Katharine McPhee/Twitter Meghan Markle and Katharine McPhee
McPhee revealed her royal connection in Jan. 2019 to celebrate her starring role in London’s production of Waitress, a role she previously played on Broadway. She shared a throwback photo with Meghan as they both smile in stage makeup — including bright red lipstick!
"Both did musicals together as a kid. one is now the duchess and the other is starring on the west end. basically the same life if you ask me," the former American Idol contestant captioned the post, adding the hashtag #tbt.
They performed in a couple shows together while both attending Immaculate Heart in Los Angeles.
"She was actually in my sister’s class — two years older than me. My sister did shows with her, I did two shows with her when I was a seventh-grader or eighth-grader. They were obscure musicals. I think one was called Yankee Doodle," McPhee previously told PEOPLE. "I don’t know if there are videos of her singing, but she’s a really good singer."
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Charley Gallay/Getty David Foster and Katharine McPhee
Meghan, who starred on the hit legal series Suits, did her acting training in theater and is a double major in theater and international relations from Northwestern University.
"She was always put together and great," McPhee told Access Hollywood.