Katharine McPhee & David Foster Sing 'Proud Mary' at Erin Foster's Wedding - Watch!

David Foster is going all out for his daughter’s wedding! The 70-year-old music producer and wife Katharine McPhee took over the stage at daughter Erin Foster‘s wedding on Tuesday night (December 31). PHOTOS: Check out the latest pics of Katharine McPhee During the wedding reception, Katharine and David performed a duet of “Proud Mary.” Katharine