Jennifer Garner boxed ''every day'' to get in shape for 'Peppermint'.

The '13 Going On 30' star portrays Riley - a mother who wakes from her coma to discover her daughter and husband have been murdered in a drive-by - in the action revenge movie and she has admitted, although she was excited about the physical challenge the role entailed, she had to do a mixture of physical activities every single day to make sure she was in the best possible shape for the film.

Speaking to 'Entertainment Tonight', she said: ''There was a lot of training, it was very physical. I was in pretty good shape going into it, and I said to them, 'You know, I know how to train for this movie, I can get where I need to go and I know what I need to do,' and they said, 'OK.' We did a lot of dance, cardio, but we also you know did crazy weights and I did bands, and did trampoline, and did everything. I also boxed every day, and then I trained with the stunt team.''

The 46-year-old actress found that she started channelling her former alter-ego Sydney Bristow - whom she played in the ABC action series 'Alias' - when they started shooting the movie - even though they both have different stories to tell.

She explained: ''At first, when we started shooting, I would be back in action mode I would just kind of fall into being Sydney Bristow. I walked liked her because my body had this memory of it. But Sydney was an optimistic young girl who was out to take care of things, but she had an optimism to her. Whereas my character Riley North [in 'Peppermint'] everything has been taken from, and she is at the depths of the depths and is coming at it from an almost animalistic point.

''There was a time I did something where I walked up the stairs and... I looked back over, and [when] I got up the stairs, I was like, 'Hang on, let me do that again, that was pure Sydney.' ''