Entourage star Jeremy Piven has been forced to deny his "diva" antics cost him the job of hosting a forthcoming fashion event in New York.

The actor hosted Fashion Rocks in 2007 but this year he has been replaced by Rescue Me star Denis Leary - amid rumors that Piven's outlandish demands infuriated staff at last year's event.

A source tells New York Post gossip column PageSix that the star demanded a separate backstage green room and insisted on rewriting the script at the last minute.

The source says, "(Piven) was a nightmare. And it wasn't even funny. (This year will see) a more trustworthy and mature host."

But a representative for Piven has denied that the star acted inappropriately at last year's concert - insisting he worked hard to perfect his onstage routine.

The spokesman says, "Not true. He had his own room, just like everyone else, and came in a week early to work on the script as expected."

Fashion Rocks - a collaboration between musicians and fashion designers - will this year feature performances from Beyonce Knowles, Rihanna and Justin Timberlake and will air in the U.S. on September 9.

- Jeremy Piven Photos

(This news article provided by World Entertainment News Network)