Celebrity Parents Katharine McPhee Celebrates Mother's Day with Sweet Throwback Photo of Son Rennie: 'Best Day of My Life' The actress shares her son with husband David Foster By Angela Andaloro Angela Andaloro Angela Andaloro is a Society & Culture Staff Writer at PEOPLE. She has been working at PEOPLE since 2022. Her work has previously appeared on BuzzFeed, Entertainment Weekly, and LittleThings. People Editorial Guidelines and Hannah Sacks Hannah Sacks Hannah Sacks is a writer/reporter for the Parents team at PEOPLE. She has been working at PEOPLE since May 2023. Her work has previously appeared in The Toy Insider, The Toy Book, The Pop Insider, and Saratoga Living. People Editorial Guidelines Updated on May 13, 2024 07:00PM EDT Katharine Foster and son Rennie. Photo: Katherine Foster/Instagram Katharine McPhee Foster enjoyed a beautiful Mother's Day alongside husband David Foster and their little boy. The singer, 40, shared a sweet throwback photo on her Instagram Stories of her son Rennie, now 3, after she gave birth to him. Sitting in a hospital bed, McPhee Foster can be seen holding her newborn, gazing down at him. "In honor of Mother's Day, share your first picture with your baby 🤍," McPhee Foster wrote across the photo. "The best day of my life." Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories. Katharine Foster Instagram Stories. Katherine Foster/Instagram David Foster Explains 3-Year-Old Son Rennie's Impressive Drum Skills: 'Figured It Out on His Own' (Exclusive) Speaking with PEOPLE ahead of the Macy's Thanksgiving Day Parade in November, McPhee Foster opened up about disagreements the couple has had surrounding their parenting styles and philosophies, a difference they both say relates to being from different generations. "I want to start disciplining [Rennie] and Kat's not really down with that," Foster said of their toddler son. "No, that's not true," countered McPhee Foster. "I just want to discipline in my own way. There's the more old-fashioned way of disciplining which involves time-outs and things like that. My take is that you can have more mindful parenting opposed to just assuming that a two or three-year-old can have time alone to reflect on what they've done poorly." Continued McPhee Foster, "I think the more new way of parenting is understanding that with a child, there's only so much that they can intellectually understand. Saying 'That was really bad, that was really, really bad,' gets into a shaming thing. I think disciplining is something that happens over time." Foster, who's also a dad to five adult children, doesn't fully subscribe to his wife's view on the matter. "David's more results-based. He's like, 'He can't just walk by and swat people'," said McPhee Foster. "Of course not. But he's 2½ and he's learning those things." Katharine McPhee realizes she baked son's iPad. Katharine McPhee Foster/ Instagram In October, the musician mom shared a hilarious moment where she was horrified to discover she'd left her toddler son's iPad in the oven, where she had temporarily hidden it at a point before. The scene unfolded in a video shared on McPhee Foster's Instagram Story, with her captioning the video, "Just over here cooking iPads," wrote adding facepalm emojis. "I tried to hide it and forgot it was in there while [heating] up the oven for my chicken special." "The iPad is in the oven because he kept asking for it," she explained as she assessed the situation, while the toddler said, "Help me, Mommy," as he realized what happened to the device.