With the critical and commercial success of "Creed," MGM is already planning a sequel to the "Rocky" spinoff -- one that could bring longtime franchise fans to their feet.

Sylvester Stallone reveals to Variety that he and director Ryan Coogler have already developed ideas for a follow-up, including a version that could see Carl Weathers return to his iconic role as Apollo Creed.

Although the character passed away in 1985's "Rocky IV," Stallone says Coogler "has some ideas of going forward and backward and actually seeing Rocky and Apollo together." “Think of ‘The Godfather 2," he teases. "That’s what he was thinking of, which was kind of ambitious.”

Another possibility takes a more traditional approach, with Apollo's son Adonis (Michael B. Jordan) facing another opponent, in keeping with the "Rocky" format.

But the biggest question looming over the sequel is Coogler's involvement. The filmmaker is in talks to direct Marvel's "Black Panther," which could limit his availability.

“I know Ryan is probably going to be gone for a couple years,” Stallone concedes. “So there will be a quandary on: Do we work with another director and have Ryan produce, or do we wait? There’s a diminishing time acceptance of a sequel. Now they are cranking them out in a year.”