Critics are heaping early praise on Taron Egerton's portrayal of Elton John in "Rocketman," which debuted at Cannes Film Festival Thursday.

The unflinching R-rated musical, which spans the career of the beloved 72-year-old rocker (a producer of the film), received boisterous standing ovations when the lights went up in the Cannes theater, bringing tears to the eyes of Egerton and John.

Robbie Collins of Britain's The Telegraph posted the earliest, glowing review, calling the musical "a heart-racing, toe-tapping, all-glitter-cannons-blazing triumph on its own terms."

Collins praised Egerton for capturing John's "look and mannerisms down to an uncanny degree, he also musters up enough of his subject’s signature showmanship to give a performance that’s joyously at peace with its own preposterousness."

As of Friday, the "Rocketman" RottenTomatoes critical score was a lofty 89% percent positive from 18 reviews tallied.

More:'Rocketman' Taron Egerton is 'at peace' as R-rated Elton John film lifts off at Cannes

The Hollywood Reporter pointed out the trailblazing depiction of the gay icon's life. "Where other studios have balked, Paramount is leading the way as the first major studio to depict gay male sex onscreen."

The film features Egerton and Richard Madden (portraying John's first gay lover, music manager John Reid) in "unflinching" scenes which depict men kissing, simulated oral sex and "a steamy bedroom scene with both Egerton and Madden unclothed," according to THR.

IndieWire editor Anne Thompson praised director Dexter Fletcher’s film as "sexy dramatic and poignant" on Twitter.

" 'Rocketman is an ambitious full-on bio musical with 20 songs—This Is Your Song got applause— sung by star Taron Egerton in a breakout performance," wrote Thompson.

THR senior editor Rebecca Keegan tweeted that Egerton is "the real deal. #Rocketman is a musical about picking yourself up off your (butt) and Taron delivers the sweat, grit and vulnerability it needs."

Variety editor Stuart Oldham called the musical "fantastic, a musical drama that hits all the right notes, especially the sad ones." He praised Egerton on Twitter as "absolutely brilliant."

Not all the viewers were overwhelmed, including Indiewire's Eric Kohn.

"If you were wondering what a great Elton John biopic looks like, don’t hold your breath," Kohn tweeted. "But at least ROCKETMAN doesn’t skimp on the music."

The Guardian's Peter Bradshaw called the film "a good-natured biopic-slash-jukebox-musical with Taron Egerton gamely doing a middleweight impersonation."

He added that the film is "better at the tiaras than the tantrums."

Party-goers posted video of Egerton and John singing "Rocketman" together at the gala afterparty.