Penelope Cruz constantly struggled not to laugh when filming 'Pirates Of The Caribbean: On Stranger Tides' with Johnny Depp.

The Spanish actress plays pirate's daughter Angelica in the latest instalment of the swashbuckling movie franchise and she admits serious scenes were tough because her co-star is so convincing as hapless Captain Jack Sparrow.

She said: "Johnny is such a funny person, he has created this amazing character.

"The main problem is that he's so funny it was hard to film the dramatic scenes, because I could not stop laughing. You never know what will happen next."

Penelope previously starred with Johnny in 2001 movie 'Blow' and says they always have a good time together.

She added to Empire magazine: "Both times have been amazing. The funny thing is, we were saying to each other, we get along so well but we play characters who always fight."