Asked by a fan about Rambo V, he replied: "We are working on it right now actually. We have teams scouting Iraq and parts of Syria where IS have their greatest strongholds. We're working with the locals there to help deliver the most intense and realistic Rambo movie experience ever."
The actor refused to divulge any further information and did not comment on the risks of working in a region where Western hostages are beheaded for propaganda purposes.
But his remarks bear out a statement from Splendor Films last year about a return for Rambo.
The German company said: "With Rambo V, Sylvester Stallone returns in his role as John Rambo.
"This time he returns to the Middle East to battle the greatest threat facing the world today, global terrorism."
Stallone's seventh Rocky film, Creed, will focus on Adonis Creed, the son of Rocky's one-time nemesis, Apollo. The young fighter, played by Michael B Jordan, wants to follow in his late father's footsteps and enlists Rocky to help him train.
The first Rambo film, First Blood, was released in 1982. It made $125million in global ticket sales - a totally eclipsed by the $300million takings of the next instalment, Rambo: First Blood Part II. The fourth film in the series was released in 2008.
- Daily Mail