Actor Robert Downey Jr. has admitted his addiction to drugs ruined his relationship with former girlfriend Sarah Jessica Parker.

The couple, who met on the set of the movie Firstborn, dated for seven years before parting ways in 1991 - after the formerly troubled Downey Jr. failed to kick his substance abuse habits.

He says, "I was so selfish. I liked to drink, and I had a drug problem, and that didn’t jibe with Sarah Jessica, because it was the furthest thing from what she is.

"She tried to help me. She was so miffed when I didn’t get my act together."