How We Met: Gael García Bernal & Diego Luna

'I don't dare say this to him because I can get sentimental – he's the brother I never had'

Gael García Bernal, 30, is an award-winning stage and film actor best known for his starring roles in 'Y Tu Mama Tambien', 'The Motorcycle Diaries' and Pedro Almodóvar's 'Bad Education'. He lives in Mexico and Spain with his girlfriend and their child

I'll have to tell you the unofficial story of how Diego and I met, because it's what I've been told by my parents since I was too young to remember. I met him when he was two days old and I was about one and my mother took me to visit him in the Mexican hospital where he was born. I think I ended up poking him in the face.

We spent a lot of time together as babies but my father remembers the first time that Diego and I really became friends. We were walking with our parents in this beautiful plaza near our homes when we bumped into each other. Diego and I greeted each other and started to play and then – being little boys – fight. Since then we've have spent most of our lives hanging out together.

He's still the same person now that I knew then. Diego has always had this beautiful energy about him. Even as a child he was such an intelligent and loving person. One thing that has changed about him, though, is his appearance – he used to be chubby; he's lost the puppy fat now.

We didn't see each other while I was studying at drama school in London, but when I returned to Mexico and we did Y Tu Mama Tambien together we really renewed our friendship. We were young, so we were discovering the language of acting and it was the most fascinating time for us. Working with friends isn't always so easy and enjoyable.

Then the film turned out to be a success so we travelled together taking it round the world. We won the Marcello Mastroianni Award in Venice. It is still one of the most memorable experiences of my life and to be able to have shared it with my best friend is a great thing. We always have a lot of fun together, but that was a particularly heavy night – we did everything.

People often ask if there is any rivalry given that we both work in the same industry but I think there is a genuine happiness at each others' success. People say that real friends are there when things go wrong for you, but I think the opposite is true. If there is anything of a competitive nature, it's that we inspire each other and want to live up to the other.

We are quite different people and our opinions are often opposed. The reason it works is that we are similar in our respect for each other, so we are always ready to listen and talk and laugh. Our friendship has developed in that when we discuss things now we can be frank and get to the point very quickly. There is a trust that means I never feel there is anything off-limits.

I don't dare say this kind of thing in front of him – because I can get very sentimental – but I think there is an English saying "He's the brother I never had." That is how I feel about Diego.

Diego Luna, 29, is an award-winning stage and film actor best known for his roles in 'Y Tu Mama Tambien', 'Frida' and 'Milk'. He lives in Mexico City with his girlfriend and child

The first time I met Gael he was just a blurry shape, because I was two or three days old and probably couldn't even recognise humans. Our mothers were really close friends, though mine died when I was quite young. Around the age of eight, Gael and I did a play together and became really close. We spent a lot of time at his house playing basketball and football – we were really competitive at that age and fought all the time.

But theatre was what we enjoyed the most – improvising and inventing stories. Even then we both knew that it was something we wanted to do, although it's not something we ever really spoke about – it was already in our lives because it was the world of our parents. We now have the same approach to work in that we care a lot about what we do and share one huge desire not to waste any time.

We've started a production company, but on Rudo y Cursi, our most recent film together, I really enjoyed just being an actor with him. I loved the breaks between filming – our characters were so silly that we just stayed in character and joked around.

Acting is about communicating, reacting and sharing – and friendship is about all of those things too. So when the actor you are working with also happens to be your best friend you get much more out of it and the experience and result is richer. We can be honest and talk to each other in a way it would be very hard to do to an actor you didn't know well.

We tease each other because we know exactly what each others' weakness are and how far we can push it – but I'm a good friend so I won't tell you what my weapons are against him. Gael takes everything seriously, but at the same time he loves to laugh; he chooses to try to be happy.

If we argue, it is usually about politics or football, even though we support the same team. Recently, we both had babies so the dynamic of our social life has had to change. Things are different now – things we might have once got excited about don't make sense when you are a father.

My favourite memory of Gael is when I saw him on stage in London in Blood Wedding. It wasn't anything to do with the play – he had just wanted to do that for so long and I was so proud of him.

'Rudo y Cursi' is out on DVD on 19 October