Video report by ITV Arts Editor Nina Nannar
Joseph and the Amazing Technicolour Dreamcoat is one of those musicals that dates past-audience-members by who was playing the main part.
In the first London show, in 1992 it was Jason Donovan but the actual musical is fifty years old. It was he who took the song into the charts.
It was Tim Rice and Andrew Lloyd Webber's first.
The musical has been seen by an estimated 16 million people worldwide.
To celebrate its big birthday, Jason Donovan is back, this time as the pharaoh - with a new Joseph and Sheridan Smith as the narrator.
Newcomer Jac Yarrow makes his professional debut on the stage as Joseph - and he's been getting some tips from his predecessor.
Watch the full interview on Youtube