There are three things Marc Martel says he won’t do to impersonate Freddie Mercury. He won’t wear Mercury’s trademark yellow jacket. He won’t go onstage wielding Mercury’s favored half microphone stand. And he won’t grow a full mustache.

Here’s the one thing Martel needs to do: open his mouth. Through genetics and musical aptitude, the 42-year-old singer is a vocal doppelgänger for the Queen frontman. That’s a gift that has led Martel, formerly the leader of a Christian band in Canada, to a lucrative second career in recent years — and a prominent but invisible role in “Bohemian Rhapsody,” the hit biopic nominated for five Academy Awards at the Oscars on Sunday. It’s not the life Martel planned, but it’s landed him on “American Idol” and in front of crowds of thousands worldwide. “I keep realizing how weird a situation I’m in,” Martel said in a phone interview. “I’m trying to keep a good head about it.”

Rami Malek embodies Mercury onscreen, but as he told The New York Times last year, “No one wants to hear me sing.” During the performance sequences in “Bohemian Rhapsody,” the movie sometimes employs Mercury’s actual vocals from the Queen archives, but that wasn’t always practical — some scenes demanded a stunt vocal-cord performer.

[Relive one of Freddie Mercury’s great moments: when Queen took “Bohemian Rhapsody” to Live Aid.]

The film’s creators have conceded that the sung vocals in the movie are largely by Mercury and Martel, although they haven’t broken down the specifics of who contributed what; doing so might distract from Malek’s performance. Martel, who received a fleeting “additional vocals” billing, acknowledged that he worked on the movie, but citing his nondisclosure agreement, would not go into detail. That leaves him with a ghostly status much like that of Marni Nixon, who provided the singing voices both of Maria in the movie of “West Side Story” (for Natalie Wood) and Eliza in the movie of “My Fair Lady” (for Audrey Hepburn), without credit.