As Ocean's Thirteen has its US premiere in Hollywood, the BBC's California correspondent, David Willis, describes how he came to appear in the film.

Don't blink or you'll miss me! - the BBC's David Willis

A few days after I registered with a casting agency, the phone rang.

The woman at the other end introduced herself as Cathy. Cathy sounded excited.

"We're casting a movie called Ocean's Thirteen," she said breezily, "are you by any chance available tomorrow?"

I did my level best to appear calm. "Just hold on a moment, Cathy, whilst I check my diary."

I put the receiver down and circled the room twice, punching the air with my fists and mouthing "Yes, yes, yes", and I then picked the receiver up again and said as matter-of-factly as I could:

"I think I can manage that. What time do you want me?"

Ocean's Thirteen is Hollywood's "holy grail", without question one of the most sought-after gigs in town.

I had taken a break from writing about movie stars for the BBC in order to become one myself - or at least that was the plan - and a wise man had told me that the best way to make it as an actor in Hollywood was to start as an extra (or "background artist" as they are known) and then shin your way up the ladder.

Every extra in town wanted the chance to say they had worked alongside Brad and George and Matt, and so a call from Cathy was a bit like rummaging through the pockets of an old suit and finding the winning lottery ticket.

Warner Brothers studios

Which would explain why everyone was perky and polite at 0500, waiting to board the bus that would sweep us through the gates of one of Hollywood's most famous movie studios - Warner Brothers - and on to the set.

Throughout all the retakes, Clooney remained personable and funny and, of course, irritatingly handsome

We were taken to stage 16, the biggest soundstage on the lot and the scene of some of the most memorable moments in cinema history.

This was where Bogart wooed Bergman in Casablanca, James Dean battled teenage angst in Rebel Without A Cause and the Caped Crusader and his sidekick Robin restored order to a lawless Gotham City.

The huge Warner Brothers sign that you see just before the opening credits clung to the side of the building - a reminder, if one were needed, that we were entering a citadel to the big screen, a shrine to the movie maker's art.

Lavish set

Crossing the threshold was truly like venturing into another world.

The set designers had built a four-storey Asian-themed casino so lavish it would have put many a Las Vegas gambling den to shame.

Ornate pillars carved with oriental dragons stood like sentries around a rock pool stuffed with real koi carp. Blood-red Chinese lanterns hung from black bamboo frames which lined the walkways between roulette tables.

Surrounding the slot machines and blackjack tables were croupiers in canary-yellow waistcoats, cocktail waitresses with expansive cleavage, high rollers, pit bosses, card sharps and dealers.

All of them extras - sorry, background artists - 600 in total, one of whom was me.

I was to play a photographer at the launch of this new casino.

The owner was about to become the victim of an audacious heist, masterminded by Danny Ocean (played by George Clooney).

Cameras, lights, action

The stars of the film line up for a photo - but where's David?

I had been given a real camera and was told to take shots of Clooney as he and others arrived for the grand opening. The sight of him drew audible gasps from many of the female cast and crew, some of whom started to giggle like overgrown schoolgirls.

The cameras rolled and we did our thing. Me and George - oh, and the rest of them.

And then we did it again. And we did it again, until the camera around my neck felt like a noose and I had lost the will to live.

And throughout all the retakes, Clooney remained personable and funny and, of course, irritatingly handsome.

When it finally became time for lunch, he slipped out of his tuxedo and took to the makeshift basketball court next to stage 16. He was good at that too, pausing just long enough to blow a kiss to a bog-eyed tour group before plopping the ball perfectly into the net.

Clooney's advice

I had previously come to grief during a break in filming by sitting somewhere I shouldn't. Barely had my bottom touched the canvas chair when an assistant director called Jody was on to me like a heat-seeking missile.

'When your name is Al Pacino, you can sit in a chair with his name on it. Now get lost!', snapped the assistant director

"What's your name?" he demanded. "Um, David Willis," I replied.

"Whose name is on the back of that chair?"

I walked around to the back to take a look. "It says Al Pacino."

"Exactly!" snapped Jody, "And when your name is Al Pacino, you can sit there. Now get lost!"

I mentioned that experience to George Clooney at the premiere the other day and he laughed in that wickedly handsome way of his.

I asked him if he had any advice for aspiring actors. He flashed a grin and said simply: "Stay out of my shot!"

Clooney and Willis: coming soon to a cinema near you.

But don't blink or you'll miss me.

From Our Own Correspondent was broadcast on Saturday, 9 June, 2007 at 1130 BST on BBC Radio 4. Please check the programme schedules for World Service transmission times.