Alan Titchmarsh has addressed the "unusual" roster of celebrities taking part in the Queen's Platinum Jubilee Celebration.Taking place on Sunday 15th May, the event will be presented by Phillip Schofield and Julie Etchingham, alongside a series of other celebrity hosts taking us back through the 70-year history of Queen Elizabeth II's reign. And Alan himself has remarked on just how grateful he is to be taking part alongside the likes of Tom Cruise, Dame Helen Mirren, Damian Lewis and Adjoa Andoh.