Reality TV has already proved it can do wonders to revive flagging broadcasting and TV careers - just look at Tony Blackburn and Claire Sweeney. Now pop has-beens are hoping it can do the same for them.

Claire Sweeney's mum didn't want her to go into the Celebrity Big Brother House. Two years ago, as the former Brookside actress was on her way there, her mum continued to try to talk her out of it. It's a good job she didn't listen to her mother.

The exposure of being on TV day in, day out for a week raised her profile considerably and helped achieve her dream job, starring in a musical on the London West End stage. "Celebrity Big Brother changed things completely," she says. These days every other programme seems to have celebrity in front of the title. There are risks for those taking part and having their every move scrutinished by fly-on-the-wall cameras. But the advantages of boosting your career outweigh the dangers as Sweeney and others have proved.

The latest contender, Reborn In The USA, may lack the word celebrity in its title but might just as well be called I'm A Former Celebrity - Get Me Back In The Charts. The musical acts will be hoping this could be the start of something big, again.

The word celebrity isn't strictly accurate. Most of those who participate in these programmes are past their prime, career-wise. They're known as has-beens in the trade. The likes of Tony Hadley, Dollar, Sonia and Michelle Gayle would be hard pressed to get TV airtime or a record release these days.

Reborn In The USA will give them weeks of primetime exposure. In return they have to sing a few songs and gamble on audiences not voting them off the bus. If there are tears and tantrums en route, so much the better for the programme-makers and the ratings.

Celebrity Big Brother was in aid of charity which, the participants would say, excuses just about anything. Equally, they know just how good a career move it can be, if they play their cards right. Sweeney didn't even win the first Celebrity Big Brother. But the way she handled herself, behaving like everyone's nice big sister, meant she emerged from the house a winner.

How unlike Vanessa Feltz who, coping with a marriage breakdown and career slump, went to pieces and started scrawling gibberish on the table in the House. Hardly a recommendation for producers looking for a presenter able to keep cool in a crisis. Anthea Turner was a loser too. If she hoped being a good sport in the house would resusitate her presenting career, she was wrong.

On the other hand, ex-boxer Chris Eubank, despite his eccentric ways, is now to "star" in his own TV reality show, an Osbornes-style fly-on-the-wall documentary series.

Comedian Jack Dee was sent to Siberia after leaving the Big Brother house as the winner - to film a BBC documentary. He was left to fend for himself in the frozen wastes in one of those celebrities-roughing-it films. He was the only one of the six who didn't really need the exposure and aggravation of being shut up with five strangers for a week. His career was doing very nicely thank you before he went through the door.

Sweeney was definitely a winner,. strutting her stuff on stage in the musical Chicago and landing her first dramatic role in a forthcoming episode of BBC1's series Clocking Off. But perhaps the biggest winner will turn out to be former Boyzone singer Keith Duffy.

Leaving the house, he landed a temporary role in top-rating soap Coronation Street and proved such a hit that his character, Ciaran McCarthy, was written back in. Even now that Ciaran has been jailed for going AWOL from the navy, viewers haven't seen the last of him. Producers plan to bring him back for another six months at least, and he could even become a Weatherfield regular.

The second batch of Big Brother celebrities are doing nicely too. Ex-Take That singer Mark Owen has a new record coming out, Melinda Messenger hosts a new daytime programme and Sue Perkins, along with partner Mel, has a regular slot on C4's breakfast show RI:SE (although, in the light of poor ratings, she shouldn't consider this a job for life).

The losers were Anne Diamond, who had to put up with insensitive jokes about her weight, and Les Dennis, whose marriage to Amanda Holden broke up under the glare of the media. His compensation was a role in the revamped Crossroads and a new girlfriend.

Tony Blackburn not only survived the horrors of the jungle and living with Uri Geller for several weeks (worse than all the snakes and creepy-crawlies, if you ask me) but saw his DJ-ing career pick up. He's got a new radio show too.

Not only did he go on I'm A Celebrity - Get Me Out Of Here, but allowed candid camera footage of his life in BBC2's The Entertainers.

In this series, performers who we thought were dead or retired (Leo Sayer, Bernie Clifton, The Krankies) were shown still making a decent living on stage, although usually at the end-of-the-pier rather than the London Palladium.

Rhona Cameron was rewarded with presenting an ITV game show, Christine Hamilton and husband Neil continue to appear on any programme that will pay them, and Nell McAndrew showed off her figure in various photo shoots. Tara Palmer Tompkinson did the round of chat shows and had a walk-on appearance in Footballers' Wives (which many would sell their souls for). Compared to that, Darren Day's reward was pantomime in Halifax, which some may consider was just reward for his behaviour towards Tara and his other companions in the jungle.

* Reborn In The USA begins on ITV1 tonight at 9.35pm.