Leann Rimes, Glee actor Darren Criss and Rumer Willis are among the stars fronting a powerful new campaign against bullying.

Singer Adam Lambert also joins the famous faces who have posed defiantly with their middle fingers held up for the camera in The New F Word Campaign, which is being launched by U.S. organisation Friend Movement.

Rimes' pal Marco Gonzalez of Friend Movement reveals the country star agreed to take part in the initiative as she has suffered her fair share of criticism over the years.

Gonzalez tells EOnline.com, "LeAnn's a great friend of mine and I've seen over the years how she's been bullied in the press, so I asked her right away to be a part of Friend Movement's anti-bullying campaign. On the day of her shoot, she was just getting over being sick and barely had a voice, but... like a true sport, she came over to our set and rocked it out.

"We had a good laugh about it. Even without much of a voice, LeAnn smiled her way through the shoot. Her photo is definitely one of our most powerful images! I think her photo and the message behind it will resonate with many around the world who have been bullied."