Justin Timberlake was probably told to "break a leg" at some point in his career. Last week, he almost did.
"Justin Timberlake sustained a muscle injury to his calf on the set of Andrew Niccol's thriller, 'Now.'" Fox, the studio behind "Now," said in a statement. "Production has taken a brief hiatus and will resume shortly."
Timberlake has since been spotted on crutches, and a source told E! News that the star is treating his injury seriously.
"He hasn't heard anything about the MRI results, but they're freezing production until he's off crutches and able to act again," the source said.
Representatives for Timberlake declined ABCNews.com's requests for further comment on his condition.
The past few months have been perilous for those in show biz. Timberlake's injury comes in the wake of a nearly fatal accident that happened on the set of "Transformers 3" in September. Gabriella Cedillo, a 24-year-old extra, ended up in a medically-induced coma after reportedly suffering a head injury while driving a car during a stunt on the film's Illinois set.
Accidents are happening on stage, too. Three actors have been injured in the Broadway version of the "Spider-Man" movie franchise, "Spider-Man: Turn Off the Dark." The show, which at $65 million is the most expensive in Broadway history, hasn't even premiered to the public -- opening night is Jan. 11, 2011.
The mishaps are just the latest to occur during the making of a Hollywood production. Below, five of the worst on-set disasters of all time.
1. "The Twilight Zone's" Triple Death. The making of Steven Spielberg and John Landis' 1983 "Twilight Zone" movie turned tragic when a helicopter accident claimed the lives of actor Vic Morrow and two child actors, Myca Dinh Le (age 7) and Renee Shin-Yi Chen (age 6). Pyrotechnic explosions caused the low-flying helicopter to spin out of control and crash. The incident led to legal action against the filmmakers, particularly Landis, who directed the segment involving the helicopter. While ultimately, no one was found criminally culpable for the accident, it led to tightened regulations on the use of child actors in special effects-heavy scenes.
2. Brandon Lee's "Crow" Killing. A budding action star's career was cut short when Brandon Lee -- son of famed martial arts actor Bruce Lee -- was accidentally killed on the set of 1994's "The Crow." The film involved a sequence in which a villain was supposed to fire a gun at Lee as he walked into the scene. Unbeknownst to the crew, a bullet was lodged in the prop .44 Magnum used during the filming, and Lee was fatally shot in the abdomen on set. He was 28 years old.
3. "Top Gun" Tragedy. Famed acrobatic pilot Art Scholl was hired to do in-flight filming for Tom Cruise's 1989 hit "Top Gun," but an accident claimed the veteran performer's life when his Pitts S-2 camera plane failed to recover from a flat spin and plunged into the Pacific Ocean. The exact cause of Scholl's crash remains unknown, as neither the plane, nor his body, were ever found. "Top Gun" is dedicated to the memory of the 53-year-old pilot.
4. "The Return of the Musketeers" Mishap. The tagline of the movie was "All for one and fun for all," but 1989's "The Return of the Musketeers" ended up being fun for no one after 54-year-old actor Roy Kinnear fell off a horse in Toledo, Spain, and broke his pelvis. He died from a heart attack the following day.
5. "Jumper's" Set Dresser Death. Special effects proved deadly on the set of the 2008 sci-fi thriller "Jumper." 56-year-old set dresser David Ritchie was fatally struck by frozen debris in Toronto, Canada, while dismantling an outdoor set in frigid conditions. Another worker suffered head and shoulder injuries that sent him to the hospital.