Her acoustic numbers included her single, Crazy Chick, now number four in the charts.

Before her performance she signed a book of condolence in Cardiff city centre for London bomb victims.

The Cardiff-born singer, who has reinvented herself since shooting to fame as a child classical star, smiled and waved at the crowd, ranging from families with children to people in their fifties.

They were gathered in the shop's aisles as she stepped out to perform the acoustic session alongside a lone guitarist.

Cloe Steward, 17, from Cwmbran, said: "She's Welsh and she makes us proud to be Welsh."

Joshua Taylor, 17, also from Cwmbran, said: "She's a crazy chick."

She joked: "I can't believe so many of you turned up - I thought it would just be my family. Thanks for coming."

Charlotte is more used to shopping in Queen Street than performing

Fans clapped and cheered after each song: Mood Swings, Casualty of Love - said to be her favourite and about her break-up with first boyfriend Steven Johnson - and Crazy Chick.

Afterwards she signed copies of the album, released on Monday, and memorabilia for waiting fans.

One of the first to the table was Natalie Primus, nine, from Cardiff, who was there with her parents Dawn and Paul and brothers Jamaal and Malik.

Natalie had a photograph of herself with Church's boyfriend, Welsh rugby star Gavin Henson, which the singer signed.

Mum Dawn said: "We're all Charlotte fans. She's a good Cardiff girl."

The Primus family were the first to meet their idol after the show

Other fans who queued to see their idol included sisters Julie and Helen Evans, from Bridgend.

Julie, 23, said: "I love her to bits. I love her dress sense and her singing." Helen, 38, said: "She's made a good move going from opera to pop."

Laura Williams, 18, from Pontypool, one of the first in the queue, said: "I like her music and she seems very cool. You can relate to her - and she likes rugby."

Bethan Preston, 19, from Newport, said: "She's got a really good voice and she can do opera and pop and R&B. She takes everything people say about her and she doesn't bite back."

The singer's mother, Maria Church, was there for the performance and later admitted the teenage diva had been nervous.

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