Now in its ninth year, West End Live, organised by Westminster City Council and the Society of London Theatre, is the largest free event of its type in the UK.
WhatsOnStage is there on both Saturday and Sunday, providing live updates and reaction via Twitter, as well as photos and analysis on Monday.
Among the programme highlights is the first glimpse of new Tim Rice musical From Here to Eternity, the cast of which will reportedly perform the 'rock-style number' "Fight The Fight".
Other West End Live newcomers will include: Burn The Floor, The Bodyguard, A Chorus Line, The Color Purple, Dirty Dancing – The Classic Story On Stage, From Here to Eternity, The Golden Voice, High Society, Let It Be, Limbo, Merrily We Roll Along, Once: A New Musical, Peter Pan: Never Ending Story, The Showstoppers and The Sound Of Music.
Shows returning this year include: Billy Elliot The Musical, Horrible Histories, Jersey Boys, Disney's The Lion King, Mamma Mia!, Matilda The Musical, Les Misérables, Monty Python's Spamalot, The Phantom of the Opera, Stomp, Thriller Live, Top Hat, War Horse, We Will Rock You and Wicked.
Click here for the full schedule