Watch Elton John and Taron Egerton's Emotional Duet at 'Rocketman' Cannes Premiere

Paramount is banking on the $41 million musical biopic as its big tentpole release of the summer.

Elton John and Taron Egerton rocked the Cannes Film Festival on Thursday evening, performing a duet on the Croisette after the world premiere of Paramount's Rocketman, the biopic of the music star, in an out-of-competition slot at the festival.

There had been much talk about a potential performance by John, 72, at the afterparty. He shot the music video for his 1983 hit "I’m Still Standing" in Cannes, and he began the surprise performance on Thursday with that song. Egerton then joined the icon to sing "Rocket Man" with John at the piano. 

John told the crowd, "This has been a very emotional night for me. ... Even if the movie doesn’t make one penny at the box office, which will kill [Paramount CEO] Jim Gianopulos, it is the movie I wanted to make." 

The film's premiere on Thursday earned a four-minute standing ovation, during which Egerton, who plays John in the film, was moved to tears and director Dexter Fletcher thanked the audience, saying, “We’re absolutely blown away by your fantastic reception.”

During the pic itself, performances of "Your Song" and "I'm Still Standing" led to loud applause from the audience, as well. 

In a recent interview with The Hollywood Reporter, Egerton recalled shooting a singing scene for the film when the music legend arrived on set. "There's really nothing more intimidating than performing in front of Elton," he said. "I don't think I could have done it if he was around a lot. But I think he knew that. He's very astute in that way."

Paramount, owned by Viacom, is banking on the $41 million musical biopic as its big tentpole release of the summer despite an R rating, some early criticism of the casting of the heterosexual Egerton in the lead role and a plot filled with sequences of substance abuse and sex.