Directed by Roger Michell (Notting Hill), performances will begin April 21, 2018, prior to an official opening May 2.
Mood Music is set in an expensive London recording studio as a young songwriter, her producer, their lawyers, and psychotherapists go to battle over who owns a hit song.
Penhall is also the author of Sunny Afternoon and Blue/Orange.
Following his role in Mood Music, Ifans will appear in Exit the King at the National Theatre in July 2018.
The upcoming production will have set design by Hildegard Bechtler, costume design by Dinah Collins, compositions by music supervisor David Arnold, lighting by Rick Fisher, and sound by John Leonard.
For more information visit oldvictheatre.com.