Selling his dog

Stallone recalls the heartbreaking moment in which he was forced to sell his beloved bullmastiff Butkus because he could no longer afford to feed the pooch as he struggled to make ends meet before Rocky.

He wrote: "It's the only thing I could sell. It was like, that was it."

Happily, Stallone was later able to buy the dog back and Butkus went to appear alongside Sly in the first two Rocky films.