The actor is said to have agreed a huge £60 million contract to return to the franchise as Captain Jack Sparrow, according to The Sun.
Depp has allegedly joined the project in order to help fund his upcoming payments to former partner Vanessa Paradis and his two children.
"Johnny is being very careful he does not sign on for too many films," a source claimed.
"He doesn't want to ruin his career with overexposure like John Travolta or Nic Cage did.
"This huge deal for Pirates means he will be able to pick his other roles very carefully on the strength of their script rather than their salary."
Johnny Depp said back in October 2011 that he would make more Pirates movies in the future.
He also stated that he is not "selling out" by starring in the action-adventure franchise.
Jerry Bruckheimer said last year that an initial script had been written for a possible fifth film.