To tell you the truth, I'm not sure quite how much actual acting was going on here from Sir Ian McKellen as he slightly updated his effort from "The Critic" (2023) and becomes legendary painter "Julian Sklar". He has long since lost his touch, and is now suffering from a terminal disease so his grasping children "Sallie" (Jessica Gunning) and "Barney" (James Corden) have a cunning plan to ensure that their nest is well and truly feathered after he has gone. This involves embroiling "Lori" (Michaela Coel) in a plan to creatively enhance (no, that's not the same as forging) some of his most…