Akshay Kumar had first worked with Ganesh Acharya in KC Bokadia's MAIDAN-E-JUNG in 1996, ever since the two have been good friends and have worked on multiple films there after. The latest being SPECIAL 26 (2013). That's probably the reason why Akshay readily agreed to be part of a special song in Ganesh Acharya's forthcoming production.
Ranveer and Ganesh had worked together in the Ad film 'My Name is Ranveer Ching' and when Ganesh spoke about his forthcoming venture, Ranveer readily agreed to be a part of it!
It wasn't difficult for Ganesh to convince Govinda for a cameo as they share a very special bond in real life. Govinda plays a drunkard in the scene. Ganesh who has made Govinda dance in a number of hits like COOLIE NO 1 and HASEENA MAAN JAYEGI, one shouldn't be shocked to see Govinda dancing in HEY BRO too.