Helena Bonham Carter is often left baffled by the jokes her partner Tim Burton shares with his best pal Johnny Depp, because she doesn't understand their references to American culture.

The actress works and socialises with the Hollywood hunk and her filmmaking husband, but admits her British upbringing leaves her confused during their conversations.

She says, "I don't actually understand what Johnny and Tim joke about. Culturally, they have had the same childhood and I haven't, so I don't get a lot of the same telly references. They try and explain what the joke is and I just go, 'huh?'"

However, Bonham Carter insists she never gets jealous of their closeness, and reveals Depp is hero worshipped by her son, Billy.

She adds, "I rejoice in the friendship! Johnny is a marvellous man and a wonderful friend. He is also godfather to our son Billy, and they have a wonderful relationship because Johnny is a dad himself. In Billy's eyes, Uncle Johnny can do no wrong."