AceShowbiz - Nick Cannon fears his ex-wife Mariah Carey will kill him after revealing the lyrics to their son's naughty Christmas song.

The actor and rapper admits he's proud of the tune his seven year old wrote, even though it contains adult themes.

"I don't know if I'm supposed to say this, but my son, maybe, like, two years ago, wrote a song," Cannon told Entertainment Tonight. "He was turning five, and he wrote a Christmas song and I was really excited."

He adds, "I told his mom like, 'Yo, he told me he wrote a Christmas song,' and she was like, 'Yeah, have you heard it...? Tell him to sing it for you next time'."

When Cannon learned the true nature of the holiday tune, he couldn't help but chuckle: "He goes, 'I saw your boobies on Christmas Eve, they were so beautiful, I didn't want to leave'," he smiled. "I was like, 'That's my boy, right there!'"

He added, "I was like, 'This is the best Christmas song I've ever heard in my life!'" Cannon added. "He sings it every Christmas!"

But the 37 year old was quick to point out that his former wife wouldn't be thrilled with his big reveal: "Mariah is gonna kill me that I told you that," he noted.

Though Moroccan's first songwriting attempt isn't exactly radio ready, Cannon is sure his children are destined for careers in music.

"They're always, like, in my studio. Like, everywhere I go, I have a studio, whether it's the house, my office, there's always a studio," he said. "My son loves to drum and my daughter does too, but she's more, like, on the piano and stuff."