From Wikipedia:
"The Nutty Professor is a 1996 American science fiction comedy film starring Eddie Murphy. It is a remake of the 1963 film of the same name, which starred Jerry Lewis, which itself was a parody of Robert Louis Stevenson’s 1886 novella Strange Case of Dr Jekyll and Mr Hyde. The film co-stars Jada Pinkett, James Coburn, Larry Miller, Dave Chappelle, and John Ales.
Filming began on 8 May 1995 and concluded on 8 September 1995. The original music score was composed by David Newman. The film won Best Makeup at the 69th Academy Awards.
Murphy portrays a university professor, Sherman Klump, a brainy and kind-hearted man who is morbidly obese. A research scientist, academic, and lecturer, Klump develops a miraculous, but experimental, weight-loss pharmaceutical, and hoping to win the affection of the girl of his dreams, tests it upon himself. Just like Julius Kelp from the original film, Klump’s vigorous, charismatic, but evil alter ego takes the name “Buddy Love”. Murphy plays a total of seven characters in the film, including Sherman and most of Sherman’s family, consisting of Sherman’s older brother, Sherman’s maternal grandmother, and both of Sherman’s parents. Sherman’s nephew is the only member of the family not to be portrayed by Eddie Murphy."
When I saw this in theaters as a kid, I didn’t know who Eddie Murphy was, and so I thought it was just two different actors playing the professor and Buddy.