Sylvester Stallone rewrote 'Rocky' after a friend tearfully told him she "hated" the character he'd created.

The 77-year-old actor became a household name thanks to the 1975 boxing movie he wrote and starred in but he revealed things could have been very different if he'd stuck with his original plan to make Rocky Balboa - a small-time club fighter and debt collector - a more "thuggish" character, having taken inspiration from Martin Scorsese's 'Mean Streets'.

In his new Netflix documentary 'Sly', the action star told how he overhauled the script after a friend read it and tearfully told him she thought the protagonist was too cruel for audiences to care about him.

He recalled: “She goes, ‘I hate Rocky. I hate him. He’s cruel. He hits people. He beats them up.'

“I said, ‘What if you stop short of it?’ Like, maybe he almost did. He could have, that’s his job, but he doesn’t?’ ‘That’d be nice.'

"I said, ‘What if he had a girlfriend or something?’ ‘Yeah, that’s nice.’ So I go back, start writing that: ‘Girlfriend. Nice.'”

Stallone also discussed being hospitalised after being "pulverised" by co-star Dolph Lundgren when filming a fight scene for 'Rocky IV'.

He said: “Dolph Lundgren… he pulverised me.

"Later that night, my heart started to swell - which happens when the heart hits the chest - and then my blood pressure went up to 260, and they thought I was going to be talking to angels.

"Next thing I know, I’m in intensive care, where I’m surrounded by nuns, and I thought, ‘OK, that’s curtains.'”

The 'Expendables' star was in hospital for nine days following the incident, praying for "one more round".

Lundgren previously discussed the incident, joking he was simply "obeying orders".

He said: “All I did was obey orders. He was the boss. I did what he told me. We came back to LA and the producer was like, ‘Hey Dolph, you’ve got two weeks off — Sly’s in the hospital.' "