Of course, Sherlock Holmes is one of the most iconic and most English characters in all of popular entertainment -- alongside James Bond -- which could explain the unexpected response Will and John received after they ran into English actor Mark Strong, who played the villain in Robert Downey Jr.'s "Sherlock Holmes."
The "Step Brothers" and "Talladega Nights" costars reunited for their farcical take on the world's greatest detective, spending three-and-a-half months in London during filming and bumped into Mark at a soccer match, striking up a friendly enough conversation until Mark asked what brought them to London.
Will recreated Mark's face after he told the actor that he and John were taking on Holmes and Watson. "He just had this astonished look," he said. "I don't know if it was anger. I don't know if it was jealousy or resentment. He was like, 'Really?'
"I think it was disappointment, I'm pretty sure," John suggested helpfully.
"Disappointment that we were handed the reigns of Holmes and Watson," Will agreed.
And there may be reason for that, as the trailer shows this is a very comedic take on the property. "We went to England and we made a lot of fun of English people," John explained. "We were not very good guests."
Fans of Will and John's easy chemistry will be pleased to know that it extends beyond the screen, as they were an absolute delight together on "Kimmel," ad-libbing and feeding off of one another's silliness just as we've seen across their respective careers.
They even paid tribute to one another, with Will sharing a story about the very bizarre code that John uses to say he needs to use the restroom. And then later and for no logical reason whatsoever, they broke into song over how happy they are to be "Reunited."
Check out their full interview above, and bizarre musical interlude in the video below: