After reading Audrey Niffenegger's acclaimed novel about a woman whose great love has a genetic disorder that makes him travel through time, the 30-year-old star was keen to secure the part of Clare in the film adaptation of The Time Traveller's Wife.
"I had read the book and dreamed of playing Clare for a while, and it was such a long time before it actually happened," Rachel recently said. "I just fell madly in love with it and knew at the back of my mind that they were doing a movie…and I just waited. Hoping."
And aside from getting to work alongside hunky Aussie actor Eric Bana, who plays her love interest Henry DeTamble in the romantic drama, there was another perk to filming as far as Rachel was concerned.
"It was fun to be 16 again," she reveals. "We spent a lot of time talking about the hair, the clothes, the make-up."
"I worked with such amazingly talented people that just a brush stroke would change my face a little bit. I looked at myself in the mirror one day and I didn't realise we were doing the older Clare that day and I said 'Oh I am looking a little haggard', before being told it was paint."
So would Rachel herself be tempted to travel back in time? "I'd be afraid I would throw it all out of whack," she says.
"But I would love to see my parents falling in love or seeing them as children. This film made me think about going back and seeing the people that you love in a different time, and how fun that would be."
The Time Travellers Wife is due for release on August 14.