Alan will be joined by cast of over 20 surprise guest performers. Show time is 6:30 PM.
Attendees can expect to hear tunes from the composer's six albums as well as his upcoming West End musical Home.
Alan's songs have been recorded by Shoshana Bean, Kerry Ellis, Eden Espinosa, Samantha Barks, Liz Callaway and Stephanie J. Block, among many others.
Tickets range from £45-£15 and can be purchased by calling the St. James box office at 0844 264 2140 or by clicking here.