Salman Khan-Sohail Khan.
However, contrary to popular misconception, Salman and Sohail aren't seen as brothers in Heroes. They play absolute strangers in the film with Salman playing the part of a Sikh army officer while Sohail enacts the role of a youngster who is on a motorcycle trip with his friend (Vatsal Seth).
What is further interesting is the fact that in each of the 5 movies that Salman and Sohail have been seen Maine Pyaar Kyun Kiya, Salaam E Ishq, God Tussi Great Ho and soon to be released Hello they have never played brothers. Guess the wait is still on to see the two Khans being truly brothers-in-arms!