Depp, 52, who is currently shooting for the next film of the series was dressed as his character during his surprise visit at the Lady Cilento Children's Hospital in Brisbane, Australia, reported Variety.
The "Alice in Wonderland" star along with actor Stephen Graham met and chatted with the children and their families for over three hours.
Fans were left overwhelmed by their favourite star's sudden visit and were seen clicking selfies with the actor.
"Now, if there's other people in it, why do you call it a selfie?" Depp said, while getting a selfie clicked with a child.
Disney's "Pirates of the Caribbean: Dead Men Tell No Tales" the fifth film of the series, is scheduled to release on July 7, 2017.