The film crew initially failed to call emergency services thinking the Hollywood legend - who suffered a vicious blow to the head in the ring - was still acting.

Stallone's mother Jackie said: "At first everyone thought Sylvester was acting when he fell to the floor, but it was serious. Fortunately he has recovered now."

Filming on the movie began in Nevada earlier this month.

Stallone shot scenes in the ring just before the middleweight World Title clash between boxers Jermain Taylor and Bernard Hopkins.

The ageing actor was desperate to make the new Rocky film after people said he was too old to revive the role.

He said: "It's all going to be about the message and the scepticism.

"Because when you reach a certain age people become sceptical about what you can do.

"You may not have the skill but you have the will and that can drive you through."

The Canadian Press BANG Media International