This is Spinal Tap sequel in the works with original cast

gamesradar.com:

A This is Spinal Tap sequel with the original cast is in the works – and it's due to be released 40 years after the first movie.

The sequel will see Rob Reiner back in the director's chair, as well as playing the documentary maker Marty DiBergi in the film. Also returning is Michael McKean as David St. Hubbins, Harry Shearer as Derek Smalls, and Christopher Guest as Nigel Tufnel – AKA Spinal Tap themselves. Tragically, Ric Parnell, who played drummer Mick Shrimpton in the film (who explodes onstage at the end), died recently. 

McKean, Guest, Shearer, and Reiner are developing the story together, but the director has also released a statement teasing what's to come.

"When it was announced that Spinal Tap would reunite for one final concert, Marty DeBergi saw this as a chance to make things right with the band who viewed This is Spinal Tap as a hatchet job," Reiner said (H/T Rolling Stone). "So he left his position as visiting adjunct teacher's assistant at the Ed Wood School of Cinematic Arts in pursuit of film history."

Reiner also spoke more to Deadline about what the sequel has in store. "They've played Albert Hall, played Wembley Stadium, all over the country and in Europe," Reiner said (the actors really have toured as Spinal Tap in the past). "They haven't spent any time together recently, and that became the premise. The idea was that Ian Faith, who was their manager, he passed away. In reality, [Ian Faith actor] Tony Hendra passed away. Ian's widow inherited a contract that said Spinal Tap owed them one more concert. She was basically going to sue them if they didn't. All these years and a lot of bad blood we'll get into and they're thrown back together and forced to deal with each other and play this concert." 

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