Bollywood megastar Amitabh Bachchan (Big B) is all set to join the cast of Hrithik Roshan's "Dhoom 4," which will be directed by Vijay Krishna Acharya, a.k.a. Victor.

Hrithik Roshan, who played the role of a thief in "Dhoom 2," returned to Yash Raj Films' tremendously successful franchise and will be playing the lead character, according to Bollywood Life.

"At the moment it is not very clear where Victor is going with this. All that is confirmed is that Aditya Chopra and Victor have approached and signed Mr. Bachchan and Hrithik," a source close to YRF said, according to Daily News & Analysis.

Yash Raj Films (YRF) is reportedly also trying to cast Salman Khan in the lead role in "Dhoom 4."

"YRF is simultaneously working on two action films; one will be Thug starring Hrithik Roshan and the other one is Dhoom 4. There have been many brainstorming sessions regarding the plot of Dhoom 4," a source close to YRF said, according to India TV.

"However, despite many interesting ideas, they are yet to finalise on one. Everyone from the team is of the opinion that Salman Khan should be a part of Dhoom 4 and take the franchise forward. There are plans to approach Salman Khan once the script is locked," the source said.

The "Dhoom" series started in 2004 and became Bollywood's best franchise after the massive success of its third instalment, which was released in 2014. "Dhoom 3" is the second highest gross film in Indian cinema history at $89 million worldwide.