Girls star Lena Dunham joked that Victoria Beckham is "too chic" to be on the show as she launched the show's third series in London.
The 27-year-old - who created, produces and writes the award-winning show, in which she also stars as aspiring writer Hannah Horvath - admitted that rumours about the Spice Girl-turned-fashion designer making a cameo appearance had been greatly exaggerated, after she said she is a fan.
"Victoria Beckham mentioned she loved the show in an interview and this has been metastasised into 'Victoria Beckham is the fifth Girl'," she said on the red carpet at Cineworld Haymarket in the West End.
"We love Victoria Beckham but she's a little chic for us."
Jennifer Konner, the show's executive producer, said she would welcome Beckham and her ex-footballer husband David on the show.
"I've heard those rumours but they have not been directly put to us. Why not? It would be amazing!" she said, adding: "And I would insist on David as well."
Lena, who looked glamorous in a monochrome 50s-style floral dress by Erdem, was joined at the screening by co-stars Allison Williams, who plays her screen best friend Marnie Michaels, and Zosia Mamet (Shoshanna Shapiro) as well as long-time fan Richard E Grant, who guest stars in the coming series.
"I have a 25-year-old daughter who obsessively watches the show. All the things she's going through are the things the characters are going through so it's a real window into the world of the young, who have left home and finished college or university and trying to make their way into the world - and the sexual politics are eye-opening, to say the least," he said.
He admitted he wasn't allowed to divulge details about his character, except that he has "a relationship with one of these younger ladies", and hopes to reprise the role in the future.
"They all really get on with one another so it felt like going to someone's house except it's work. And Lena is a very unassuming boss - she is astonishing. She has such authority but does it effortlessly without being diva-ish," he said.
The third series of Girls will premiere on Sky Atlantic on January 20.