She may be a chart-topping pop star but Billie Piper still needs singing lessons.

And when the teenage pop queen decided she needed a little fine tuning she turned to a former Sussex schoolgirl.

Classical singer Izzy - alias Isobel Copper, 25 - has been working with 17-year-old Billie for four months.

She said: "Billie wanted someone young and hip to bring her along. I agreed to do a course of lessons with her before she went to Japan to do a big showcase, providing she bonded with me.

"She did and I was like a big sister to her. I thoroughly enjoyed working with her.

"She is a very down to earth, genuine type. She told me how bad my life could become and I told her not to let anyone take her shine away.

"I also told her not to let the media get her down. Working with her made me realise how grateful I am to be 25 because I feel it's easier to put your foot down when you need to."

Izzy has been helping Billie to perfect her breathing technique which, she says, is the basis of a good singing voice.

She plans to continue teaching the 17-year-old star but has mixed feelings about becoming famous herself.

She is currently waiting to see if her new album Ascolta will follow its predecessor, Libera Me, to number one in the classical chart.

She said: "I don't think I'm a celebrity at the moment and I don't know if I will become one. I would like to sell loads of records and also have a normal life but I don't know if that is possible."

Irrespective of how well she does, Izzy is keen to continue teaching. She is particularly keen to work with pupils at her former school, St Bede's in Eastbourne.

She said: "I started singing there and it was extremely significant and special in starting me out as a singer and musician.

"I was the head chorister so I travelled around Sussex with the choir and we performed at all sorts of private functions and parties in places including Alfriston and Brighton."

When Izzy returned to St Bede's in March to perform in a millennium concert she was surprised to find photographs of herself on the walls.

Headmaster Christopher Pyemont said: "When she came down in March she sang so beautifully.

"To see someone famous performing at the school who was an ex-pupil was so inspiring for the pupils. We would love to have Izzy back to give some lessons to the pupils."

Izzy, who now lives in London, is particularly keen to inspire young people to take up classical music.

She foresees a return to classical, opera and folk music.

She said: "There are so many boy bands and girl bands at the moment they just seem to blend into one.

"I hope this will trigger people to return to classical music and see where they can take it."

Ascolta is currently at number 12 in the classical charts.