Wahlberg reveals his co-star objected to the idea of the former rapper and Calvin Klein underwear model acting alongside him in the 1995 film.
He tells The Hollywood Reporter, "Leonardo was like, 'Over my dead f**king body. Marky Mark's not going to be in this f**king movie'.
"We'd had a thing - I didn't even realise it, (but) I was a bit of a d**k to him at a charity basketball game. So he was like, 'This f**king a**hole is not going to be in this movie.'"
But casting director Avy Kaufman urged DiCaprio to change his mind and at least meet with Wahlberg.
The Fighter star adds, "I come in and I do the audition and I kind of look at him and he kind of looks at me, and then we do a scene, and they're like, 'Hmm, this f**king dude's pretty good, right?' The next thing you know, boom, we're hanging out."