Joaquin Phoenix refused to recreate his maniacal Joker laugh for a cinemagoer after he made a surprise appearance at a movie screening.
The 44-year-old actor is enjoying huge success with his titular role as the Batman villain in Todd Phillips' dark take on the origin tale, which also stars Oscar winner Robert De Niro, Frances Conroy, and Zazie Beetz.
The Walk the Line star started his movie theatre tour on Saturday by stopping at the Universal Studios AMC for a 4pm IMAX screening, before heading to downtown Los Angeles and the Alamo Drafthouse Theatre, where he popped up after the end credits of multiple screenings.
At one such screening, Joaquin was fielding questions from cinemagoers when one pleaded with him to "do the laugh" - referring to the Joker's maniacal half-laugh, half-cry, which the actor admitted took him a while to perfect.
But while the three-time Oscar-nominated actor appeared a good sport in answering other questions from fans inside the cinema, he seemed less willing to grant that request, insisting to the man: "I can't do it. You do it - I wanna see you do it!"
As the fan hit back that "I'll do it if you do it", the screen star still refused, giggling awkwardly before telling the crowd: "Anyway, I hope you have a good weekend. Thank you guys for coming out - I do appreciate you supporting the movie."
Joaquin's surprise appearances took place during the movie's record-breaking opening weekend. It has taken an impressive $93.5 million (£76 million) domestically, earning more than the rest of the U.S. box office top 10 combined, and a staggering $234 million (£190 million) worldwide, making it the highest-grossing October release ever.