This is one of the plays listed on Rupert’s CV from when he was studying with LAMDA. It is a musical, with book and lyrics by John Dempsey and music by Dana P Rowe, that premiered at the Donmar Warehouse, London in 1997 (Wikipedia).
Rupert played the character Cal Chandler, with directors Anne Durham and Stephen Jameson.
I’m not entirely sure of the year, but I’m guessing the first half of 2004 (i.e. at the end of the 2003-04 academic year).