Katharine McPhee, 38, kisses top of son's head while celebrating Father's Day with David Foster, 72

Katharine McPhee and Andrea Bocelli perform Elvis' Can't Help Falling In Love at Hollywood Bowl

Katharine McPhee Performs Elvis Song with Andrea Bocelli at the Hollywood Bowl & Again at Private Event!

Katharine McPhee, 38, joined by her husband David Foster, 72, while heading to morning show