"We love each other," Holland said about Gyllenhaal before detailing a memorable workout he had with the actor at a gym.
Holland said he initially didn't want to workout with Gyllenhaal who he praised as being in great shape. The Spider-Man star also stated that he is very competitive and wanted to match or exceed the workout Gyllenhaal was doing.
"There's a law in the gym that you can't run slower then the guy next to you," Holland said about wanting to outshine Gyllenhaal while on a treadmill despite getting tired early. Gyllenhaal made things harder for Holland as he kept suggesting to run longer and at a steeper incline.
Holland was game to do anything Gyllenhaal was doing, however, and even suggested longer run times.
"We're doing press later that day and I can't walk," Holland said about the aftermath of the hard workout. "I'm sitting there and a journalist goes 'What's wrong with you?' and I said 'Well I do all of my own stunts.'"
Spider-Man: Far From Home is set to arrive in theaters on July 2.
Holland's Late Show apperance also included the 23-year-old taking part in a Rescue Dog Rescue segment with Colbert. The duo presented a number of stray puppies who need a home, telling fictional stories about each canine in order to help with their adoption.
The puppies were each given Marvel-themed names such as Spider-Pup and Black Widdle.