(LOS ANGELES) -- Vin Diesel isn't happy with the progress of Fast & Furious 7, but apparently some people associated with the movie think the actor has been a problem himself.
Sources tell The Hollywood Reporter Diesel has been so difficult that some on the set wish they could use the facial-replacement technology being used to insert co-star Paul Walker in the film on Diesel as well.
Walker died in a car crash last November, before his scenes were completed.
According to one insider, "Vin spent a whole day in his trailer one day. The next day, they waited four hours for him.”
The source adds, “He called a meeting [May 28] of studio execs to his trailer for two and a half hours to say, 'What the f**k am I doing here?'” The next day, work was done with doubles.
Another source confirms that progress has been frustrating, noting the crew is suffering from "low morale."
However, Universal Pictures chairman Donna Langley denies the reports, telling the industry publication, "This production is working through some challenges that are historically unprecedented. The crew and cast, led by Vin, have been nothing but terrific under these circumstances."
Fast & Furious 7 is slated for an April 2015 release.
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