Katharine McPhee Shares Clip of 3-Year-Old Son Rennie Drumming Onstage

Katharine McPhee, 39, and David Foster's, 74, son Rennie, three, makes drumming debut at their show: 'Had a VERY special guest join us on stage'

Katharine McPhee and David Foster's Son Wows Playing Drums on Stage

Katharine McPhee's 3-Year-Old Son Impressively Plays the Drums Onstage at the Kennedy Center