He may be the Mad Hatter in the upcoming blockbuster "Alice in Wonderland," but this summer Johnny Depp will be heading to Hawaii to shoot the fourth installment in the popular "Pirates" franchise, "Pirates of the Caribbean: On Stranger Tides."  For awhile, Depp openly questioned whether a fourth installment would ever occur.

After Depp's longtime friend Dick Cook was essentially fired as Chairman of Walt Disney Studios early last Fall, the superstar raised some doubt over whether he still wanted to return for another go around as Captain Jack Sparrow.  Depp revealed today that it was actually the dismissed Cook who helped convince him to still do the picture.

"I had a very good conversation with Dick Cook who is someone I admire greatly and that helped," Depp said.  "And also we're going to come at it with a different angle at it.  And [director] Rob Marshall has a completely different take on it."

What that "take" is remains to be seen, but so far changes include the addition of Penelope Cruz in a mysterious, but prominent role.

However, "Stranger Tides" is a long way off for Depp at this point.  He'll soon head to London for the Royal World Premiere of "Alice" and still has endless questions ahead of him about his seventh, yes, seventh collaboration with director Tim Burton.  The biggest surprise?  It turns out Burton didn't have to approach his old friend with a hard sell to make the movie.

"To be honest he could have said Alice and I would have said [yes]," Depp tries to get out as the assembled press erupt in laughter. "I would have done whatever character Tim wanted. Certainly the fact it was the Mad Hatter was a bonus and a great challenge. And to try and find this guy and not just to be a rubber ball that you heave into an empty room and bounce all over the place, But also to bring a little bit more of history or gravity to the guy."

Depp embraced the role by doing research not just into Lewis Carroll's books, but into the origin of the term "mad as a hatter."  It turns out the glue hat makers used to use had high levels of mercury in them which had severely adverse side effects.

"So, [I looked at him] as damaged goods -- physically damaged and a little obtuse -- instead of this hyper nutty guy," Depp recalls.  "He could go from one second high fluting and a lot of levity and then into some dangerous, potential rage and some tragedy."

Burton adds, however, "Being that it was a Disney movie, we tried to not focus so much on the Mercury poisoning aspect. "

One of Depp's other major concerns was the fact he's used an English accent a number of times already in films such as "Finding Neverland," "Chocolat" and "Charlie and the Chocolate Factory."  Depp notes, "You've got to really pay attention to where you have been. That's the great challenge. You may get it wrong. There is a very good possibility you could fall flat on your face. I think that's a healthy thing for an actor."

With Burton by his side, Depp was asked if his kids had a favorite movie in the now growing Burton/Depp library.  Without a beat Depp says "Edward Scissorhands."

"They connect with the character and I think they see their dad feeling that isolation -- that loneliness and he's a tragic character," Depp says. "They bawl everytime they see it."

Starting on Tuesday Johnny Depp will be starring opposite Angelina Jolie in the new thriller "The Tourist."  As the session ended, Depp was asked to comment on what should turn out to be one of his increasingly rare contemporary roles.

"I think it will be swell. I like the French film I liked it a lot and my friend played the part in that and I liked it and I thought it might be interesting to explore this character," Depp says. "You never know what's going to happen. I suspect there might be a few paparazzi in Venice."

And a circus even the Mad Hatter would find daunting

"Alice in Wonderland" opens in 3-D and IMAX nationwide on March 5.