Despite the claims for decades, Charlie Chaplin does not appear as his Little Tramp character in "The Nut." This was debunked by film historian Jeffrey Vance in his 2008 book "Douglas Fairbanks." Vance writes, "It is clearly a Chaplin imitator, not Chaplin himself, who appears briefly in the party sequence wearing the Tramp costume."
In the final days of production, Douglas Fairbanks was injured while filming a stunt. As noted in the 26 Feb 1921 Motion Picture News, Fairbanks's toe caught on a windowsill through which he was supposed to jump, "landing on a man passing by on the side walk outside." The botched jump resulted in a broken bone in Fairbanks's left hand, and an unspecified back injury. Although some reports claimed the actor had to recuperate in the hospital "at least five weeks," Motion Picture News insisted that, the day after the accident, Fairbanks returned to the studio lot, where he posed for still photographs with "prominent" visitors.