Ryan Reynolds Gushes Over Jodie Comer's 'Haunting Version' of Mariah Carey's 'Fantasy' in 'Free Guy'

Ryan Reynolds is in awe of his Free Guy costar Jodie Comer.

In the new action-packed comedy Reynolds plays Guy, a bank teller whose humdrum existence is upended by the arrival of Molotov Girl (Comer), a mysterious spy on a dangerous mission.

Like his character, Reynolds, 44, tells PEOPLE he became immediately "obsessed" with Comer, 28, when he saw her in her Emmy-winning role as a psychopathic assassin on BBC America's Killing Eve.

"To work with her lived up to that and then some," Reynolds gushes while seated next to her. "Sorry, I'm talking about you like you're not here."

Comer, who appears flattered by her costar's praises, deadpans: "I paid him to say that."

Watch the full episode of People Features: Ryan Reynolds & Jodie Comer on PeopleTV.com or on the PeopleTV app.

But what impressed Reynolds most about his costar might surprise fans.

"Do you know that Jodie sings in the movie? I always tell everyone this, because they don't realize it's her," Reynolds says excitedly. "Right at the end of the movie, you hear the song 'Fantasy' come on, but it's not Mariah Carey singing."

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Reynolds calls Comer's rendition of the hit pop song the most "haunting version." "It's really gorgeous," he gushes, to which Comer replies, "Thank you, Ryan."

Free Guy director Shawn Levy (Night at the Museum) elaborated on the song's inclusion in his film during a press conference, as reported by Digital Spy.

"Ryan is a maestro of the odd random, but inspired, song idea," Levy explained. "He is obsessive about it.

"Early on when we were working on the script, Ryan's like, 'You know what I think should be the anthem of this entire movie and marketing campaign', and he suggested this song by Mariah.

"Little did we know that by the third act of the movie, we'd have a cover of that song by our very own Jodie Comer in the movie."

The Deadpool star also shared that prior to using the song in the film, he got in touch with the Grammy winner, 51, proving to be a strong member of the "Lambily" — the name for Carey's fandom.

"I got to speak with Mariah and talked to her a little bit about how much of an engine and an agent of progress that this song had been in terms of our creative process and the scripts," he told Variety. "She's just been awesome about it."

Free Guy is in movie theaters on Aug. 13.

For more about Free Guy pick up this week's issue of PEOPLE, on newsstands Friday.