Sir Elton has a "significant" role in Kingsman: The Golden Circle, according to Taron Egerton.
The singer will play himself in the sequel to 2014's Kingsman: The Secret Service and the movie's star says he did a "superb" job on set and was very amusing with it.
The 27-year-old said: "You've never seen him like this, he's hilarious in it.
"It's quite significant, as well. It's not a walk-on. He's there. He's in the movie.
"He plays himself, but it's a significant role and he's so funny. He's superb."
Taron also says he was thrilled to get to work alongside the 70-year-old pop legend as he's his "hero."
He added to Digital Spy: "I mean, it's such a treat for me, as well. He's such an icon and, as for many people, a little bit of a personal hero of mine. And yeah, he really brings it."