The model and late night host donned '80s-inspired workout clothes and tried their best to match what they were seeing on-screen from Jazzercise instructors.
The dance moves included high kicks and having to repeatedly jump up and down.
"That's kind of like the '80s version of the dab," Upton said about Fallon attempting to perform a monkey-themed exercise routine.
Upton and Fallon ended the challenge by paying homage to 1983 film Flashdance. The pair energetically ran in place before they sat down to have a bucket of water poured onto them.