The actors have been shooting for the movie in Jodhpur.
"I shot with Amitji last night itself. It's true that he has pain in the shoulder and back. But this film also has a lot of action scenes for him. I think it is after a lot of years that you will see Amitji doing a lot of action. So, it's definitely a challenging film for him and he is coping very well with it," Aamir told the media here.
"He has had a shoulder and back injury. The pain had got aggravated day before, but he is better now," he added.
Aamir, who is in Mumbai just for a day for his birthday, celebrated his special day with media persons.
The actor hopes "Thugs of Hindostan" reflects the hard work being put in.
"I hope the work we are doing on 'Thugs of Hindostan' is good and people really like it. I want that the film that I am working in with Amitji is memorable. This is my expectation from the film," he said.
The movie, being directed by Vijay Krishna Acharya, also features Katrina Kaif and Fatima Sana Sheikh. Parts of it are being shot at Jodhpur's Mehrangarh Fort, from where Big B has been sharing some picturesque updates.
In his blog on Tuesday, he revealed his health was not up to the mark, and that's why doctors were called in from Mumbai to "fiddle around" with his body.