Writer-director Leigh Whannell just announced on Twitter that Dermot Mulroney will star in Insidious: Chapter 3, the latest pic in the franchise produced by Jason Blum’s Blumhouse, Oren Peli and James Wan. Plot and character details are being kept under wraps but the threequel also stars Jem and the Holograms‘ Stefanie Scott, who was cast earlier this month. Focus Features has set an April 3, 2015 release date in the U.S. Shooting begins July 7. Mulroney, repped by WME, was most recently in August: Osage County and the Steve Jobs biopic Jobs.