Gary Oldman wore Sid's real chain necklace in the movie. When doing his research, Sid's mom gave him the necklace to wear during filming.
Gary Oldman lived on a diet of steamed fish and melon to lose enough weight to play the emaciated, heroin-addicted Sid, and was hospitalized when he went too far and became malnourished.
In a later interview, John Lydon was asked the question, "Did the movie get anything right?" to which he replied: "Maybe the name 'Sid'."
According to Gary Oldman, he disliked the script, and dislikes punk music, but he accepted the role because of the salary, which was £35,000.
Sid vicious' mother Anne Beverly initially tried to prevent the movie from being made, but after meeting with Alex Cox, she decided to help the production. Gary Oldman visited her while researching the role, and described her as "very warm and open and helpful."