The late Pete Postlethwaite's involvement in Killing Bono -- the last film he made -- was an "amazing honour" for all those who took part, its director said.
The Oscar-nominated actor, who died in January after a long fight with cancer, plays a camp landlord in the film about two brothers who fail to crack the music industry while their schoolfriends U2 shoot to worldwide fame.
Speaking at the comedy's UK premiere, director Nick Hamm said the young cast was hugely grateful to have had Postlethwaite on board.
"He was one of the greats, and to have him on your set was just such an amazing honour," he said.
"The last speech that he has in the film is about fame, what fame can do to you and how fame can both destroy you and make you."
Based on music critic Neil McCormick's autobiographical book I Was Bono's Doppelganger, the film shows the aspiring rocker, played by Ben Barnes, and his brother Ivan -- Love/Hate star Robert Sheehan floundering while arch rivals U2 soar to stardom.
Attending the premiere in London with his sibling, McCormick revealed his former U2 classmates had given the film their seal of approval.
He said: "Bono loves the film, he's supported it all the way through. I know that they saw it in Australia, the whole band, and they were rolling around laughing at Adam Clayton's hair -- mind you, we were doing that in 1977.
"It was funny then, it's still funny now."
Referring to Barnes's dashing role in the Chronicles Of Narnia franchise, McCormick added: "If you're going to be played by an actor, it might as well be Prince Caspian and Robert Sheehan.
"I wanted them to cast Danny DeVito as Bono. That would've been the ultimate revenge."