A leading popstar whose face was all over billboards this summer was secretly shooting an upcoming film in Poland, here’s everything you need to know.

Charli XCX made waves with her chart-topping album “Brat.” Now, she’s set to star in the upcoming film Erupcja, filmed under the radar during the height of ‘Brat Summer.’

Variety reports that the singer stars alongside playwright and actor Jeremy O. Harris (Emily in Paris), Lena Góra (Roving Woman), and Will Madden (Jethica), with filmmaker Pete Ohs at the helm.

Erupcja, which translates to ‘eruption’ follows a volatile relationship between a foreign woman named Bethany (Charli) who visits her unnamed friend in Warsaw, Poland. It has been dubbed a ‘city movie’ which means the Polish capital is a central character in the flick.

Charli XCX is set to star in upcoming film that she secretly filmed during ‘Brat Summer’

Despite the film staying under wraps, fans had spotted the artist in Warsaw in August and suspected she was working on a new project.

Twitter account FilmUpdates then burst the secret open with a post that stated: “Charli xcx has co-written a film with Jeremy O. Harris that is currently in production in Poland. She will also star in the film, directed by Pete Ohs.”

Speaking to Variety, Harris revealed that shooting was difficult because fans kept recognising Charli in public. He recalled one night when they were filming in a nightclub: “It was almost impossible to shoot, which was insane. Every single person in the club was like, ‘Oh my god, Charli XCX is here to do a secret performance.’ And it was like, ‘She is, but not the one you think.’ We were shooting the same week Obama put her on his playlist as well, which is hilarious.”

Since the rumours have been confirmed, fans have taken to social media to share their excitement. One X user exclaimed: “Oh my god it’s real???” Another chimed in praising co-writer, Harris: “With Jeremy O. Harris writing you know it’s gonna be awesome. Can’t wait.”

Harris is no stranger to the limelight, with TV roles in popular shows like Emily in Paris on Netflix, and theatre writing credits for productions such as Slave Play, which sparked controversy when it came to the West End this summer.

Charli is set to feature in several upcoming films. These include an R-rated remake of the 1978 horror film Faces of Death, the thriller I Want Your Sex opposite Olivia Wilde, and a graphic novel adaptation of 100 Nights of Hero starring Emma Corrin. Benito Skinner recently announced that Charli would also appear as a guest star on Amazon Prime’s college comedy series , Overcompensating.

Erupcja doesn’t have a confirmed release date yet.