The song - 'Aaya re aaya bodyguard...' not only has Shera dancing and grooving with Salman but will also be seen doing a small act with Katrina, sources said.
The song, which was shot recently at Filmcity will have Shera coming in as Katrina's bodyguard and signalling to Salman that he is guarding the actress, the sources added.
Shera says he was a little apprehensive initially about the dance moves in the song.
"This is for the first time I am in front of the camera with Salmanbhai doing this item song.
He just showed me some dance steps and I did a lot of rehearsal before the final take. It was scary and I was nervous. I will never forget this experience," Shera said.
"I have shot the song with Salman Bhai and all this seems like a magic. Salman bhai is such a huge star and for someone like him showing such trust in me is nothing short of a miracle.
He said that this is my most trusted man in front of the whole world. Isn't that great?," he added.
Earlier, Shera had unveiled the theatrical promo of 'Bodyguard'. Directed by Siddique and produced by brother-in-law Atul Agnihotri, 'Bodyguard' stars Salman and Kareena Kapoor.
"It was Salman's idea to rope in Shera for the song. I am sure audiences will love it," Agnihotri said.
'Bodyguard' is a remake of 2010 Malayalam movie of the same name. It is set to hit cinema-houses on August 31.