IT’S every entertainer’s mantra – leave them wanting more.

But mezzo-soprano Janet Shell was surprised to find herself applying it in a chance meeting with David Beckham’s children.

The performer, who grew up in Port Sunlight, was singing at the 2007 christening of Geri Halliwell’s daughter, Bluebell Madonna, in the garden of the former Spice Girl’s house.

“It was great. We were left to our own devices in the marquee in the garden and her little dog was coming round and barking at us and eventually she came and took it away,” recalls Shell.

“Posh was there with Brooklyn and Romeo and they were very cute and running around and they asked us ‘are you going to sing again?’ But actually we weren’t.”

Shell, who used to walk home from Wirral Girls Grammar School pretending she was Julie Andrews, is used to performing for well known figures.

She has sung for John Major at 10 Downing Street, coached Hot Chocolate’s Errol Brown and entertained guests at a party to mark Peter Sissons’ last day at the BBC with a rendition of The Leaving of Liverpool.

Last September, she appeared at the wedding of TV actress Sophie Winkleman to Lord Frederic Windsor in Hampton Court Palace.

“An email came in from the man who runs the Chapel Royal there saying ‘do you happen to be free in a couple of weeks’ time’,” she recalls. “You’re not going to turn that down!”