About 5,200 volunteers gathered on the steps of the Sydney Opera House to pose nude for artist-photographer Spencer Tunick on Monday morning.About 5,200 volunteers gathered on the steps of the Sydney Opera House to pose nude for artist-photographer Spencer Tunick on Monday morning. (Rick Rycroft/Associated Press)

Spencer Tunick's latest art-photo installation in Australia drew more than double the expected turnout, with approximately 5,200 volunteers gamely doffing their clothes early Monday morning to pose nude in front of the Sydney Opera House.

Volunteers began queuing before dawn to participate in the U.S. artist-photographer's installation, which included a series of images shot outside as well as inside the iconic Australian landmark.

People of all ages, backgrounds, shapes and sizes posed, embraced and mugged for Tunick — best known for his distinctive photos of nude figures in public spaces.

'It doesn't feel sexual, it just feels tribal, a gathering of humanity.'—Participant Art Rush

Participants included a woman pregnant with twins who was set to be induced for labour later Monday, rugby players, doctors, teachers and even a local TV personality, who turned away from the camera to film a segment for his morning show.

"I'll never get a chance to do this again; it's not worth being inhibited," Art Rush, a 19-year-old student and participant, told reporters.

"It doesn't feel sexual, it just feels tribal, a gathering of humanity," he said. "I thought it would be all old people and nudists, but everyone here is great."

Monday's Sydney event, dubbed The Base, was comissioned as part of the city's Gay and Lesbian Mardi Gras Festival.

"It was difficult to get the straight participants to embrace the gay participants and vice versa," Tunick said afterward.

Tunick had also invited Lady Gaga, who recently professed to be a fan of his work, to participate as well, but there were no reports of the outrageous pop star at the shoot.

"So I was very happy that that last setup finally got done and everyone came together [in a] united, friendly kiss, a loving kiss in front of this great structure."

The Sydney installation, which organizers had initially expected to draw just 2,500 volunteers, ultimately surpassed the 4,500 that turned up for Tunick's 2001 shoot in Melbourne.

He has also photographed his installations in Mexico City, Montreal, New York and Switzerland.