Ethan Shanfeld Forty years after making his directorial debut with the 1984 cult classic “This Is Spinal Tap,” Rob Reiner will begin filming the follow-up to the music mockumentary in February. Plus, the fictional heavy metal band will apparently be joined by real-life music legends Paul McCartney, Elton John and Garth Brooks, Reiner revealed on the “RHLSTP With Richard Herring” podcast. Christopher Guest, Michael McKean and Harry Shearer are set to return as the members of Spinal Tap, alongside Reiner as the documentarian Martin “Marty” Di Bergi.