Movie star Denzel Washington has heaped praise on Samuel L. Jackson for beating his past drug demons.

The actor admits he can only imagine how tough it must have been for his friend and peer to conquer his much-publicised addictions at the beginning of his career after watching another pal, Whitney Houston, stumble and fall as a result of her substance abuse issues.

Washington tells GQ magazine, "She had done so well in recovery. And that is the toughest part about addiction... That was a monster drug that got a hold of her, it was a mean one. You can't go back to that one. Nobody beats that.

"I look at people, and I don't think I'm speaking out of line... Sam Jackson, I've known for 30-some-odd years; he was down at the bottom. And he came all the way back. And when he cleaned up, he never looked back.

"But he can't have that beer, because it might lead to the tough thing."

Houston lost her battle with addiction earlier this year (Feb12) and was found dead in her suite at the Beverly Hills Hotel.