Madonna refused to wear the clothes provided for her character on Will & Grace, according to executive producer Gary Janetti.

The Vogue singer appears in a 2003 episode of the TV sitcom as Liz, who Megan Mullally's character Karen meets at her office job and they become roommates.

During an appearance on the Behind the Velvet Rope with David Yontef podcast, Janetti revealed that Liz didn't look anything like what they had planned because Madonna insisted upon using her own wardrobe.

"(She's) like an executive secretary, the kind of woman who wears her sneakers on the subway and carries her shoes in her bag and goes to a happy hour after work and thinks she's kind of like, you know, a big deal in her tiny office," he explained. "So she was supposed to wear, you know, Anne Klein II suits with sneakers and be the kind of woman you'd see on the subway. And Madonna as that is very funny.

"But Madonna didn't want to wear any of those clothes so she wears very long blonde hair extensions and these outfits. So she looked fabulous, but as a result, it was about 50 per cent less funny than it should have been."

He revealed that Madonna came to set with her own wardrobe and glam team "at the height of her fame" and the crew knew that trying to convince her to wear the character's clothes "wasn't a conversation that was going to happen".

"We even had jokes we had to change because of what Karen said - maybe based on what she was wearing - (because it) didn't make sense anymore," Janetti added. "I mean, she looked like Madonna. She looked like a rich, fabulous celebrity, which wasn't what the character was. But she was game when she was on the show, and she was also funny."