As she makes her soap debut with a guest role in Coronation Street, Sarah Harding tells Susan Griffin about her 'nerve-wracking' first scenes and keeping in touch with the Girls Aloud clan

Coronation Street (ITV, 8.30pm)

AS a life-long Corrie fan, Sarah Harding was ecstatic when offered a guest role in the popular soap, but managed to abide by the rules and keep the information to herself.

"Well, I told my mum and fella," confesses the 33-year-old, but when the news finally broke, the Girls Aloud singer didn't quite get the response she'd been expecting. "No one believed it. I was like, 'Yeah, it's true'," exclaims Harding. She's playing Joni, the glamorous wife of chef Robert (Tristan Gemmill), who recently turned up in Weatherfield keen to rekindle things with ex Tracy Barlow (Kate Ford).

"It's going to be a bit of a shock for Joni. She's moved up to help with the restaurant and he's obviously still holding a torch for Tracy, which she's not happy about," reveals Harding, who had a baptism of fire filming at a restaurant in Didsbury, Greater Manchester.

"I was thrown into the deep end, I really was. I started filming with Kate, who's actually the exact opposite of her character in real life. It was really nerve-wracking. There were paparazzi and it was a really long day with a lot to learn."

Her character makes her debut tonight, when she turns up on the cobbles looking for Tracy, although the pair won't come face-to-face until tomorrow night's episode. It wouldn't be Corrie if there wasn't a dramatic slap, but "it was choreographed", Harding points out. "Health and safety."

It was during a visit to the Street last year that the idea of Harding making an appearance came about.

"I said I was a really big fan of the show and I had a wonderful time getting pictures outside the Rovers and Roy's Rolls," recalls the singer, who's appeared in Freefall and the St Trinian's sequel. A short while later, producer Stuart Blackburn got in touch. The plan for now is for Harding to appear in a several episodes.

"Obviously, I'd love to come back and do some bits and bobs, but I've got my music coming out so there's loads of stuff going on," says Harding, who was born in Ascot but grew up in Stockport.

It's now 13 years since she, along with Cheryl Fernandez-Versini, Nicola Roberts, Kimberley Walsh and Nadine Coyle, won the TV talent show Popstars: The Rivals, and landed the No 1 spot as Girls Aloud. They went on to have 20 consecutive top ten singles and six platinum-selling albums and reunited for a tour in 2012 to mark their tenth anniversary.

Now Harding's on the cusp of forging a solo music career, with her debut single Threads set for release next month.

"It's really exciting, it's quite a gritty song. I co-wrote it and was in a bit of a bad mood that day," she reveals with a laugh. "It's quite rock chick, which people might expect because I was always a bit of a rock chick in the band, but with a poppy edge to it."

The Girls Aloud clan have all "been great, really supportive and congratulating me", she says. "I saw Kimberley and Cheryl a few weeks ago. But we're all so busy, it's impossible to get us all in one room at the moment. I was supposed to be there the other week when they were all together, I arranged it, but missed out because of work."

Harding was once known as a wild child and party girl, but after spending time at a rehab facility in 2011, reportedly for alcohol abuse, depression and sleeping pill addiction, she now says she likes nothing more than pottering around her home in Berkshire.

"I have five animals and lead the country life now. I've got a veggie patch and everything."