Jack Black waited 15 years to ask his wife on a date.

The 43-year-old actor admits he was so shy as a teenager he couldn't even approach the woman of his dreams to start a conversation, despite having plenty of opportunities to seize the moment.

Speaking to The Sun newspaper for a 'What I wish I'd known at 18' article, Jack said: ''I wish I'd had more courage to ask out Tanya Haden, the woman who eventually became my wife. We met at school at 18 - and I wasted 15 years waiting for my chance.

''She was everything I could wish for. Talented, beautiful and a wonderful performer on stage. She was part of a band called The Haden Triplets. We first worked together on a student film but we did not date.

''I use to see her and her sisters perform at clubs around town. I would watch from the shadows, mumble some compliments and shuffle off. So I would see her only every couple of years.''

Jack - who has sons Samuel, six, and four-year-old Thomas with Tanya - also revealed he lived a ''rebellious'' lifestyle when he was younger and smoked a lot of cannabis.

He said: ''I was a wild and rebellious youth. I did get mixed up with some shady characters early on and can remember driving in cars, at speed, out of our heads.

''I also met Kyle Grass, my partner from Tenacious D, at around 18. I would go to his apartment and he would give me guitar lessons in exchange for a cheeseburger. We smoked a lot of pot, played a lot of guitar and fantasised about become rock stars. We eventually made our fantasies come true.''