Katharine McPhee and David Foster are celebrating their son's first birthday. The 37-year-old singer and actress and 72-year-old musician hosted a safari-themed party for their son, Rennie, on his birthday Sunday. McPhee posted a photo on Instagram Stories of her wearing a crepe paper headband made to look like a lion's mane. "My baby is turning 1," she wrote alongside three sobbing emojis. McPhee also shared a photo of a play area with a ball pit and a toy zebra. McPhee and Foster married in June 2019 and welcomed their son in February 2021. Foster also has five adult daughters, Allison, Amy, Sara, Erin and Jordan, from previous relationships. McPhee posted a photo in June 2021 of herself holding her son while shopping with a friend. McPhee called motherhood the "greatest job" she will ever have during an interview on "The Kelly Clarkson Show" in April 2021. "He's such a good little baby and I'm so in love," she said of Rennie. McPhee is known for playing Karen Cartwright on "Smash" and Paige Dineen on "Scorpion." She most recently starred in the Netflix series "Country Comfort."