Sylvester Stallone is planning to develop a new biopic about legendary boxer Jack Johnson.

The 71-year-old star has created a new company, Balboa Productions, in the hope of developing more TV and film projects, and one of Stallone's ambitions is to deliver a biopic about Johnson, who was the first African-American heavyweight boxing champion.

Johnson has recently been in the news after US President Donald Trump decided to pardon the sporting icon, who was arrested in 1912 due to his relationship with Lucille Cameron, which violated the Mann Act against ''transporting women across state lines for immoral purposes''.

Supporters of the boxer - who was originally convicted by an all-white jury before fleeing the US - have been campaigning for him to be pardoned for years.

And President Trump granted the request in April after holding talks with Stallone.

The Hollywood icon has, of course, already enjoyed great success with boxing movies, having created the money-spinning 'Rocky' franchise in the 1970s.

Stallone is now returning to the genre with the biopic, which he's creating in a partnership with MGM, according to Deadline.

But, in the short term, Stallone is currently focused on 'Creed 2', which is due out later this year.

The follow-up to the 2015 hit 'Creed' is being directed by Steven Caple Jr., rather than Ryan Coogler, who previously admitted to being disappointed that he's not been able to continue with the franchise.

Explaining why he's not directing the sequel, Ryan shared: ''There's timing, and that film for whatever reason it had to go when it's going. I think it's a blessing that it's going, man.

''It's amazing that they found an incredible filmmaker in Steven Caple Jr., who's a guy I actually went to film school with, who I have a lot of love and respect for. I can't wait to see what he does with it.''