First came love, then came marriage, then came a baby... err not quite in that order!

Newly-engaged reality TV star Jack Osbourne confirmed to CNN's Piers Morgan tonight that he and fiancé Lisa Stelly are expecting their first child.

This is grandchild number five for his heavy metal legend father Ozzy Osbourne, who already has four grandchildren; two each from daughter Jessica and son Louis from his previous marriage to Thelma Riley.

Osbourne expressed some nerves about becoming a father, telling Morgan, ""I guess I do have something to tell you, I am about to be a father. I'm excited. I'm a little nervous."

Ozzy, on the other hand, jumped for joy and hearing the news, saying "I'm shocked. I think it's fabulous."

Adds Osbourne's mother Sharon, "I'm happy because it's what Jack wants so I'm happy, and I've always wanted to be a grandma so it couldn't be better."

Jack recently produced 'God Bless Ozzy Osbourne,' an entertaining documentary about his famous father.

Watch a Trailer for 'God Bless Ozzy Osbourne'