Birkett, who plays Dionne, came to prominence alongside Gates, landing fourth place on the first season on Pop Idol when she was only 16 - Gates was pipped at the post and beaten to the top spot by Will Young. She has since appeared in a number of West End and touring musicals including Priscilla Queen of the Desert, Thriller Live and Respect La Diva.
Amy Diamond, who takes on the role of Sheila, was a finalist on Andrew Lloyd Webber and the BBC's search for a Dorothy, Over the Rainbow. She has also been seen on tour in Craig Revel Horwood's tribute to singer-songwriter Neil Diamond Brother Love's Travelling Salvation Show and on the London fringe in Upstairs at The Gatehouse's production of The Drowsy Chaperone.
Hair, has book and lyrics by Gerome Ragni and James Rado and music by Galt MacDermot. The score includes numbers such as “Aquarius”, “Ain’t Got No”, “I Got Life”, “Good Morning Starshine”, "Let the Sun Shine In" as well as the title song.
Following its Liverpool engagement the musical will travel to the Churchill Theatre, Bromley; Manchester Opera House; the Alexandra Theatre, Birmingham; the King's Theatre, Glasgow; the New Theatre, Oxford; the Grand Theatre, Wolverhampton; the Alban Arena, St Albans; the Marina Theatre, Lowestoft; the Grand Theatre, Blackpool and the Mayflower Theatre, Southampton where it plays its last confirmed date on 21 July 2012.
Further casting and dates have still to be announced.
Hair is produced by EJB Entertainment and Charles Aerts Entertainment in association with The Booking Office.