Former England rugby star James Haskell is set to fight in mixed martial arts.  (Photo: AFP)

Former England flanker James Haskell, who retired from rugby in May, has signed a deal with a mixed martial arts (MMA) promoter and plans to make his heavyweight debut next year.

Haskell, 34, hung up his boots after struggling to overcome recurring ankle and toe problems after decorated rugby career that included winning 77 caps for his country.

However, he is now prepared to put his body on the line in promoter Bellator's heavyweight division.

"The journey begins and I could not be more excited," Haskell posted on Instagram.

Haskell has previously worked as a television commentator on MMA and admitted to practising martial arts as part of his training while still competing at the highest level during his rugby career.