The Irish director of The Angry Birds Movie has admitted he was "sceptical" about turning the hugely popular app into an animated film.
Fergal Reilly said Hollywood's record of adapting video games for the big screen was "patchy" because some film-makers were a "slave to the source material".
But the former storyboard artist from County Louth said he had a "huge amount of freedom" to produce "an entire world" based on the Angry Birds games which have been downloaded more than three billion times.
Speaking at the film's premiere in Los Angeles, Fergal told the Press Association: "I was probably just as sceptical as anybody else.
"As soon as a read the first two pages, it was like a paradigm shift. There is very clever comedic writing and it's a very clever expression of the game.
"In fact, it's leaving the game behind and creating this whole new thing."
Fergal - directing his first film - said he was "fascinated" to see the upcoming big screen adaptations of Warcraft and Assassin's Creed after previous attempts to turn video games into movies had been "hit and miss".
"It's been very patchy," he said. "We were allowed to blue sky the entire world and all the creatures that live in it. We had a huge amount of freedom.
"If you're a slave to the source material, it's going to be very difficult to please everybody and you end up really disappointing people because you haven't changed their expectation.
"You've tried to match what the original source material was like too much, without really going for a blue sky and saying, 'I'm going to leave this behind and turn it into something brand new'."
Actor Josh Gad, who voiced Olaf in Disney's Frozen, said he was "beyond cynical" about playing one of the characters in The Angry Birds Movie, which also features the voices of Sean Penn, Jason Sudeikis and Blake Shelton.
Josh told the Press Association: "When I got the phone call I said, 'There are a few words that worry me about what you just said ... The Angry Birds Movie. Those four words are concerning me. I was basically like, 'Why do we need this?'.
"The producer said, 'Give me five minutes of your time' and by minute one I realised this was so much more than an adaptation of a video game.
"It had a great message, amazing characters and was so fun."
The Angry Birds Movie is in UK cinemas from Friday.