Sherlock star Mark Gatiss gives a "tour de force" performance as George III in a new production of Alan Bennett's play about the king, according to reviews.
The Madness of George III at Nottingham Playhouse is "a perfect star vehicle" for Gatiss, according to The Guardian's critic Kate Maltby.
The Telegraph's Dominic Cavendish agrees, saying Gatiss had come "into his own as a leading theatre actor".
Bennett's 1991 play shows King George battling a mystery mental illness.
Nigel Hawthorne won an Olivier Award for playing the troubled monarch in the original production and went on to reprise his role in the 1994 film.
Cavendish gave the play five stars and saluted the way the Gatiss "keeps drawing out more from himself, coiled entrails of pain, confusion and fear, while somehow retaining his lovability".
According to The Stage, the League of Gentlemen and Game of Thrones actor "rises to the challenge" of following in Hawthorne's footsteps and "turns out to be very good casting".
Critic Natasha Tripney wrote: "Gatiss's performance is very physical. He makes the most of his height, stalking the stage, splay-toed, as he conveys the king's rapid decline."
Gatiss also drew high praise from Nottingham culture website LeftLion, whose reviewer Jared Wilson said Gatiss was "excellent, engaging and energetic throughout".
Debra Gillett and Adrian Scarborough also appear in Adam Penford's revival, which will be screened live in cinemas on 20 November.
George III reigned from 1760 to 1820, during which time Britain lost its American colonies in America's war of independence.
The king makes a cameo appearance in musical hit Hamilton, in which he is seen berating the revolting colonists for "making him mad".
As well as his acting roles, Gatiss has written for Sherlock and Doctor Who.