Tuesday saw the launch event for the brightest, bubbliest, biggest musical around, as the cast of Hairspray arrived at Birmingham’s New Alex Theatre. The show will be this year’s big Christmas musical at the Alex, following on from Jersey Boys and Ghost in 2014 and 13 respectively. I was very lucky to be invited to the launch, where the All star cast performed a series of key songs from the musical, and also hosted a Q&A session with the audience. Hairspray is the story of Tracy Turnblad, an overweight teenager who becomes a dance sensation in early 1960s Baltimore. She finds love with the teen idol Link, but also gets…