The 38-year-old actress admits she's not big on celebrating birthdays, but she needed something to cheer her up while she was filming in Canada last year (14).

"I was just so sad playing this woman that my favourite memory is that birthday on this film," she tells WENN. "I had about 12 people from all over the United States fly to Toronto for the weekend. It was really, really special.

"They completely brought sunshine with them and (co-star) Tom (Hiddleston) went out with us and we all went to eat dinner and had dance parties and karaoke and ping pong. It was probably my favourite birthday I've ever had.

"The only thing you could do to remind you of the goodness in your life is to be around your loved ones, which is why it was so important to fly my friends in for my birthday to say, 'This is not real. There is this other life'."