Ian McKellen seemed like a sure fit for the role of Professor Dumbledore after Richard Harris’ death, but McKellen said he firmly declined the offer from producers when approached about the part. Speaking with BBC World News in 2017, McKellen explained that he turned down the role because Harris had disliked him, and he didn’t feel comfortable taking over for someone who didn’t believe in his talent.
“When they called me up and said would I be interested in being in the Harry Potter films, they didn’t say in what part,” McKellen revealed to the BBC. He then added, “I worked out what they were thinking, and I couldn’t … I couldn’t take over the part from an actor who I’d known didn’t approve of me.”
For reference, Harris had made a comment about McKellen’s acting abilities several years prior, and he wasn’t very flattering in his remarks. According to ET Online, Harris said that McKellen was “technically brilliant but passionless.” It was this comment that deterred McKellen from taking over the role, or robe, of Professor Dumbledore. The part eventually went to Michael Gambon who continued his portrayal for the remaining six movies in the “Harry Potter” series.