There is not a lot of preparation involved in asking me to get naked! 
From escaping death and changing the course of the world in cult indie hit Donnie Darko (2001) and appearing as Jennifer Aniston's brooding boyfriend in The Good Girl (2002), Jake Gyllenhaal has quickly emerged as one of the most promising young actors of his generation. He then enjoyed a brief stint in the West End in This Is Our Youth before getting caught up in the tangled web of celebrity - first by being linked to the Spider-Man role following complications with Tobey Maguire around the time of the sequel and then for dating Kirsten Dunst. Disaster flick, The Day After Tomorrow (2004) followed but Jake's star really soared in 2005 with roles in Ang Lee's Brokeback Mountain, Proof and Jarhead (all of which are due for a 2006 release in the UK). Here he talks about the rigours of boot camp and getting into the mindset of a bored and occasionally naked marine for Jarhead.
You lobbied for the role very hard. Why?
As soon as I read this book I fell in love with it but when I heard Sam Mendes was directing I thought there is no way I am ever going to get that part. Then strangely enough I heard a couple of months later that Sam wanted to meet me in a diner in New York. We met and he handed me this script and said: "I'm not offering you the part but I want to hear what you think of it." I read it and told him that I loved it and that I wanted to do it and he said "Heh, heh, heh, of course you do." Then began our sado-masochistic relationship.
I remember calling him and saying that maybe I shouldn't read for it because I'm not very good in auditions. But I read and I was horrible and then I didn't hear from him, so I called him on the phone and said I was perfect for this part and would do anything to play it and he never called me back! It continued like that until a couple of months later I got the part. It was a long audition process.
Can you now begin to understand the terror that young men must feel going into war?
No, I don't think I was really able to understand that. It did put me on the periphery. I experienced what a Marine would experience to become a Marine and then also a little bit of what it's like to wait to fight. There was also a little bit of action but it came with the exception of the threat of being killed or killing someone ourselves, which I think is what it's all about. With that in mind, I could feel something when I put on the uniform and when I had my head shaved. I remember putting on the flak jacket and the helmet for the first time and feeling all of the energy in my body turning inwards. I remember that feeling of being sucked in.
Did your physical training help when it came to the semi-nude scene? And how did you prepare for that? Did you need much persuading?
If you knew me at all you would understand that there is not a lot of preparation involved in asking me to get naked! The training and getting in shape involved was primarily for the role and that was my real way in. I felt I needed to get into shape to understand the idea of becoming a Marine. But when the story and the people involved are as good as they are I will do pretty much anything for it. If you don't believe me, wait until you see what I've been through in movies this past year.
As for the scene itself, it was one of those that as an actor you go through and read but the only dialogue that was written was Merry Christmas. So I moved on to the scenes where there was more dialogue and more fun. I was really more interested in those until I found myself sitting naked in the desert with a Santa Claus hat on my crotch!
What was it like working with Jamie Foxx? Did he try and lead in the same way as his character in the film?
I think he's like a ray of light - no pun intended, but I really do. Whenever he is around there is an air of positivity. I remember two days before the Academy Awards we were shooting the scene in the oil. It wasn't oil but burnt molasses, brown sugar and black food dye. We were all covered in it and Jamie was sitting there on this really windy, cold day for something like two hours while they were figuring out something with the rain machine. He didn't say much of anything, but gave a smile or made a joke here and there. I thought this man is about to win the Academy Award and he is covered in oil and he is still having a good time and not a complaint is coming out of his mouth. That was how it was from the very beginning. Even Sam would use it as an example when he was punishing us.
What was your worst experience of boot camp?
My worst experience was waking up in the middle of the night with a glass bottle hitting my head. I later found out that Lucas Black [co-star] decided to throw a bottle into the air to see where it landed and it landed on my head. I think I cumulatively got eight hours of sleep over the five days that we were there. But by the end of it I said to myself as we were driving back: "Remember this feeling of going back into civilisation because this is the only little taste you are going to get of what it actually feels like."
What's next for you?
I'm doing a movie right now called Zodiac with Mark Ruffalo and Robert Downey Jnr. David Fincher is directing and it's about the Zodiac Killer - the serial killer in San Francisco in the late 60s and early 70s. It's a true story and it's very David Fincher and very good, hopefully. Then again, if it's not good, David will make it good.
What were the war movies that inspired or really affected you in some way?
[Sarcastically] The war movies I grew up with were Navy Seals and GI Jane, which were two extraordinary films that were truly inspirational to me. They really helped me to do nothing in the movie.
Jarhead is released in UK cinemas on Friday 13th January 2006.
