Actress and singer Katharine McPhee says being a mother is the best job she will ever have.

The Smash star gave birth to son Rennie David, her first child with her producer/composer husband, David Foster, in February, and though she's exhausted, Katharine couldn't be more thrilled with her special delivery.

"I'm a little bit tired here and there but I find times to nap," she tells fellow mom Kelly Clarkson on her U.S. daytime talk series The Kelly Clarkson Show, "and he's such a good little baby. I'm so in love, it's my greatest job I'll ever have."

Katharine is so in awe of baby Rennie right now, she can't believe she will ever need to tell him off if he misbehaves when he is older.

"My girlfriend was doing my hair today and she was like, 'Can you even imagine that you're going to have to get mad at him one day?'" she adds. "(And I said), 'No, he's so sweet right now. I can't imagine'."