Johnny Depp loves playing Captain Jack Sparrow in 'Pirates Of The Caribbean' because he has no boundaries.

The 47-year-old actor - who will be seen for the fourth time as the swashbuckling hero in the forthcoming 'Pirates of the Caribbean: On Stranger Tides' - relishes the chance to play him because there is no limit to what he will do.

He said: "You can do whatever you want, essentially. He's a free spirit."

However, the Hollywood hunk does admit loving the character so much can cause "problems" because he is never ready to let go and will perform scenes multiple times.

He said: "The problem is with me is that I enjoy every scene to the point where the director is saying, 'Do you have his yet, are you done?' "

Johnny is so fond of the character he made a surprise appearance at a London school following a request by a British schoolgirl who wrote a letter to him.

He has also dressed up as the pirate for other charity events including a visit to London's Great Ormond Street Hospital.