The 36-year-old Smash alum is pregnant with her and the 70-year-old music producer's first child, a source confirms to E! News. In photos published by People on Thursday, the couple could be seen out shopping for baby items this week in Montecito, California.
"Katharine has always wanted to be a mom and to have a baby with David," a source tells E! News. "They weren't necessarily trying for a baby but were open to it happening this year. Since work has slowed down for both of them, they knew this year would be a great time for it to happen."
"They told their immediate family members about a month ago and everyone was very shocked and excited," the insider continues. "Erin Foster joked that their kids will be the same age."
Foster is also dad to Erin Foster, Amy Foster, Sara Foster, Allison Jones Foster and Jordan Foster.
This baby news comes just over a year after McPhee and Foster tied the knot. As fans may recall, the couple said "I do" in June 2019 during a romantic ceremony at the church of St. Yeghiche in London.
"It was a very quick but traditional ceremony," a source told E! News. "Katharine looked stunning in a classic Zac Posen simple white gown."
Ahead of the ceremony, the "American Idol" alum took to her Instagram to gush about her relationship.
"Exactly 13 years ago today my very first single, 'Somewhere Over The Rainbow,' was released right after Idol. Today... I'm marrying the man who produced it," she wrote. "Life is full of beautiful coincidences, isn't it? Thank you for taking me over the rainbow, David."
In Nov. 2019, the couple appeared on TODAY to dish about their romance and their recent nuptials.
"We met on American Idol when I was a contestant and he was a mentor with Andrea Bocelli," McPhee shared. "I have always just admired him and loved him and he's always been so great to people around him. He can be intimidating when he really needs to be for his work, but he's really lovely."
Foster also revealed how McPhee first caught his attention.
"Her singing, first of all," he said. "I mean where do I start the inner beauty, the outer beauty, and we have been friends for 14 years, and it was just kind of a natural coming together."