A sequel to "The Expendables" is reportedly on the work. The thriller earned an estimated $35 million across the United States and Canada during its first three days of release. This is the biggest opening for Sylvester Stallone who directed and co-wrote the film.

Stallone told Hollywood Reporter that a script for a sequel is "plotted out in [his] mind's eye." The 'Rocky' star said that he 'believe[s] this group has to continue to evolve."

There might be a change in actors line-up though. Stallone said "it just can't become the same people." Introducing to the new people into the group and taking out other people from the film are the challenges for the planned sequel.

Stallone, 64, was last in theaters with 2008's "Rambo" and 2006's "Rocky Balboa." They opened to $18 million and $12 million, respectively.