In Last Christmas, Clarke stars as a down-on-her-luck store clerk at a holiday-themed novelty shop who meets a mysterious handsome stranger -- played by the appropriately handsome Henry Golding -- who encourages her to pursue her passion for performing.
Clarke and Golding recently joined ET's Nischelle Turner in studio on Wednesday, and the former Game of Thrones star -- who described the Paul Feig-directed project as an "incredibly optimistic hopeful story" -- opened up about performing Michael's beloved tunes, including the Wham! hit the film gets its title from.
"I don't do my own stunts but I do do my own singing," Clarke said with a laugh, before explaining how she got over her initial intimidation over the prospect of doing justice to the tunes.
"I was aware that that would be too much pressure for me to be like, 'It's George Michael! I'm singing to George Michael!'" Clarke recalled. "[But then] I kind of realized that the words that I were saying were so poignant for the character, and that I was telling her story, and it's just that George Michael was giving me the vehicle with which to do it."
The music of the late pop superstar -- who died on Christmas Day in 2016 -- plays an integral role in the film, and the soundtrack even includes one of Michael's previously unreleased tracks.
"George Michael is literally [like] another character in the whole movie," Golding explained of the singer's emotional presence in the project.
While filming in London, ET paid a visit to the set and spoke with Oscar-winner Emma Thompson -- who wrote the screenplay and plays Clarke's mother -- and she opened up on how she secured the rights to Michael's beloved music.
According to the actress, Michael gave the project his blessing before he died in 2016, and his estate provided the film with a previously unreleased track. Check out the video below to hear more about the music-infused holiday love story.
Last Christmas opens in theaters Nov. 8.