Wahlberg, 39, plays the role of boxer Micky Ward in the new Oscar-nominated movie and Bale, 37, plays his half-brother Dicky Eklund in a role which has already won him a Golden Globe for Best Supporting Actor.
Wahlberg also produced the movie and he revealed how Bale was given the part.
He said to UK newspaper The Sun: 'There were a lot of other actors who flirted with playing the part but ultimately no one stepped up and said: 'OK, I'm willing to go to this place'.
'When I saw Christian at our daughters' school, I thought about his roles in Rescue Dawn and The Machinist and I knew that, physically, he could do this.
'So I approached him in the playground of this school and said: 'Dude, I have this movie and I want you to read it.' He read it, responded right away and committed to the project.'