Was Gandalf's head bump in The Lord of the Rings a happy accident or inspired improvisation? Peter Jackson's The Lord of the Rings trilogy is a timeless adaptation of the original books by J.R.R. Tolkien, and a huge part of that success can be attributed to the quality ensemble cast. While The Lord of the Rings made household names of virtually everyone involved, undoubtedly the biggest star of the movies was Ian McKellen, playing the wizard known as Gandalf. The legendary actor embodies his part in Tolkien's Middle-earth perfectly, and would later return to appear in the Hobbit trilogy.
Among the idiosyncrasies and mannerisms that make up McKellen's Lord of the Rings performance, there comes a moment in The Fellowship of the Ring where Gandalf brushes his head on a chandelier in Bilbo's Shire home and then swiftly turns around and bumps his head hard on a low beam. It's a relatively minor moment in an epic movie trilogy, but an important one nonetheless. The scene helps humanize the mysterious and celestial figure of Gandalf, while also serving to further drive home the size difference between wizard and Hobbit - one does not belong in the world of the other.
Perhaps the most interesting aspect of Gandalf's accident, however, comes from behind the scenes, as there are 2 different versions of how the head bump idea came about. According to Peter Jackson in the DVD commentary for The Fellowship of the Ring, McKellen's bump was completely unscripted and the actor genuinely knocked himself on the elaborate set, but stayed in character, acted through the pain and performed so well that Jackson used the shot. This "happy accident" anecdote would be an interesting movie moment in itself, but the filming of the scene is made even more compelling by Ian McKellen's slightly different recollection of events.
In a 2004 interview, McKellen was asked about Jackson's recollection that The Fellowship of the Ring's head bump was unintentional, and replied by saying the director's account wasn't entirely accurate. Instead, McKellen claimed that although the moment wasn't scripted, he had come up with the idea before shooting and hit his head intentionally, believing it would add something to the scene. Given the differing accounts, it seems that McKellen planned the bump ahead of time but didn't tell Jackson, leaving the director to believe the knock had been genuine. Due to the original anecdote from Jackson, many The Lord of the Rings fans believe that Ian McKellen really did hurt himself while filming the scene in Bilbo's house, despite the actor's response.
However the detail came about, the accident is a worthy addition to Gandalf's character and a prime example of an actor fully understanding their character. The fact that Jackson, and presumably others on set, thought that McKellen had hit himself for real is testament to the thespian's acting ability, and while it's possible that McKellen might be claiming ownership of the incident to cover for an embarrassing filming mistake, the Lord of the Rings star should probably be given the benefit of the doubt.