Hollywood action man Sylvester Stallone was "embarrassed" when he was inducted into the International Boxing Hall of Fame back in 2011, because he didn't feel worthy enough beside fellow honouree Mike Tyson.

The actor was celebrated at the Canastota, New York venue for turning the spotlight on the sport in his Rocky film franchise, but he felt out of place next to real boxing icons Tyson and former World Boxing Council Middleweight Champion Julio Cesar Chavez, Jr.

Stallone says, "I was actually embarrassed by it (Hall of Fame honour) because I'm not a fighter, but they look at it like someone who helps promote boxing (sic). Mike Tyson and Cesar Chavez, Jr. is (sic) amazing so it was another validation that I'm here promoting the sport.

"But I've always loved the sport even when I was a kid, seven or eight years old, just fascinated with this idea of two men just showing their hearts and going for it."

Stallone steps back into the ring for new release Grudge Match, co-starring Robert De Niro, and director Peter Segal admits he was a little intimidated at the prospect of working with the movie hardman on the new boxing comedy.

He explains, "I was both elated and scared. I had watched (director) John Avildsen's commentary on Rocky and how meticulously Sly had gone through a beat by beat choreograph of 'left, left, right, right, left, right,' everything. And so I realised there is no person on the planet earth who has choreographed more cinematic boxing matches than this guy.

"But then there was a story that I had laid out and one that I had to convince him would be the right story to tell. I had to convince Sly that this was a way to do an interesting story without holding a gun and killing someone. We worked together but I didn't know how that was gonna go at first."