Inside Over The Rainbow's first show

On Wednesday night I went to the recording for this Saturday's studio show of our new BBC One series Over The Rainbow, hosted by Graham Norton and starring Andrew Lloyd Webber.

We're searching for a Dorothy to appear on the West End stage next year. As the BBC's controller of entertainment commissioning I get to attend recordings of all the shows my team and I commission.

Our new panel of highly expert judges - Sheila Hancock, Charlotte Church and John Partridge were great. And, of course, the girls - 20 Dorothys - performed astonishingly well at this early stage of the series.

Sheila, John and Charlotte are already working very well together. Sheila knows everything there is to know about acting and is passionate about bringing on and nurturing new talent. Charlotte, although still young, has been a professional singer for so many years she knows all there is to know about voice and performance.

And John, before he shot to fame as Christian in EastEnders, was a star of musical theatre in the West End, performing in Cats and Starlight Express amongst others.

Each brings something different but vital to the panel and each manages to say something constructive or insightful - watch out for Sheila's comments about pop music!

The girls performed in groups of four, each group with a mentor - a current West End leading lady - Kelly Ellis (soon to replace Jodie Prenger as Nancy in Oliver!), Ruthie Henshall (currently appearing in Chicago), Sheridan Smith (Legally Blonde), Tamzin Outhwaite (Sweet Charity) and Melanie C (Blood Brothers).

This is an entirely new format for us but I really think we will be seeing more of it as it gave an added dimension to the singing.

It was never going to be easy getting 20 down to 10 aspiring performers for the live studio shows. The standard is extremely high and I was very encouraged, especially as some are so young (ages range from 16-28).

After much heated debate Andrew and the panel managed to agree on seven who would go through. Then with an even more heated exchange they came up with the next three who have made it through to the live shows and the public vote.

Andrew is brilliant in these discussions, very quickly and concisely focusing everyone's minds on what we need our Dorothy to have. Every time you sit in a room with Andrew you learn something new about musical theatre. His enthusiasm for new talent and the performing arts never seems to diminish.

And revenue from the phone votes on this series will go to the Performing Arts Fund - a small BBC charity, but one which gives students who otherwise wouldn't be able to afford it the opportunity to study musical theatre.

In fact it's the biggest funder of musical theatre training - within the charity sector - in the UK and has supported over 100 students to date with awards totalling over £600,000.

So we have our 10 girls for the live shows. There is, however, one place left. It's down to you - our viewers now.

You get to choose in a phone vote which girl gets the wildcard entry place into the live shows. The winner will be announced during the first live show on 3 April.

The confidence and ability amongst our Dorothys is amazing but then that is what the series is all about - unearthing wonderful talent that exists in this country, nurturing it, watching the potential being fulfilled and seeing it blossom into marvellous West End talent.

Make sure you tune in to watch the excitement, the tears and the drama!

Mark Linsey is controller of entertainment commissioning