We can't say we're entirely surprised that HBO's forthcoming The Idol and Euphoria exist in the same cinematic universe, given their oft-controversial content and their shared creator, Sam Levinson, but we didn't exactly anticipate seeing Euphoria characters cross over into the hard-partying world of pop star Jocelyn and her entourage. However, that could be a possibility between the two shows, at least for one Euphoria star.
As noted by Vulture, Alexa Demie, who plays Maddy Perez, makes a cameo in the first episode of The Idol as "a woman hanging at the club where Jocelyn and Tedros meet." It's not specified if she's playing Maddy at said club, but it's not outside of the realm of possibility given that Euphoria's high school students act like full-grown adults and would absolutely be out clubbing. Maddy has always had a sophistication and grown-up glamour that her classmates couldn't quite replicate, so if she were to be hanging out with a bunch of celebrities and their hangers-on, it would feel well within the character's personality and penchant for dressing up in fabulous vintage gowns and going out. As noted by PopCrave, Levinson did confirm the two shows are set in the same universe.