Mumbai -- Katrina Kaif is the new fitness instructor for Salman Khan, who himself has been a mentor for several young actors in the industry. Khan and Kaif are paired together in Kabir Khans next Ek Tha Tiger. Salman has undertaken the task of training her on the sets regularly. Katrina really takes her workout and fitness regime very seriously. And shes so into her training these days and at her fittest best that Salman joked about taking fitness tips from her, says the source. After Khans surgery, Katrina is more concerned about Khan stressing on his workout regime. This concern prompts Salman to joke further, Salman has been ribbing Katrina about being the hottest fitness instructor of sorts, reveals a source from the sets.