Jake Gyllenhaal plans to celebrate his 30th birthday in the Arctic scuba-diving with walruses.

The 'Love and Other Drugs' star reaches the landmark age on December 19 and will be joined by his family for the sub-zero adventure in the in the Arctic Circle.

He decided on the unusual trip because he wanted to do something completely different.

Jake said: "The only reason I'm doing it is I wanted to do something that absolutely terrified me - killer whales and walruses and freezing cold water? That seems absolutely terrifying."

The actor - who is rumoured to be dating Taylor Swift - insists he is no longer worried about saying goodbye to his 20s after having a conversation with his older sister Maggie Gyllenhaal, who is 32.

He added: "I was talking to my sister the other day about being 30 and celebrating the life you've had up to this point. I feel there's a massive sort of sea change coming in myself and I'm psyched."

Ahead of his plans to swim with walruses in the Arctic, Jake recently revealed he feels as though the start of the next decade of his life marks a new beginning.

He said: "I'm not 30 yet, but I definitely feel more like myself. I feel like now, it's just the beginning. I guess you get to a point at 30 or somewhere and you say, 'What I am, is what I am and that's what I'm going to be and that's all good. I don't need to be anything else.' And that's kind of how I feel."