Johnny Depp's '21 Jump Street' cameo was "crucial" to the movie

He told movies.ie: "It's like stepping into the 'Star Wars' world, and trying to avoid Darth Vadar. It was pretty crucial to me that Johnny came on board for a cameo. Once he agreed, it was a case of finding a funny way to do it. I reckon most people - if not all - will be hard-pressed to spot him until he steps forward. Johnny's a great sport, and always up for a laugh, so, he was pretty much game for anything. In the end, he felt it was cathartic too, a chance to say sorry, in a way, to his co-stars for bailing on them."

Jonah always wanted to see a big screen adaptation of the show and is thrilled he is the one who has made it happen.

He said: "In America, the show was a very big deal. And it was such a neat idea for a comedy, I always had it in the back of my mind that someone should try and bring it to the big screen one day. I never thought it would be me. Well, I say that, but I was always secretly hoping it would be me, of course."