Peter plays the lead character in The Worst Thing Ever - Darren Graham, who is having a tough time coping with his parents' split.
Peter, 10, from Surrey, tells us about himself.
"When my mum was younger, she was shy.
She didn't want us to be shy, so she got my big brother into acting. I just wanted to copy him, and then I started really enjoying it.
I was about seven or eight when I started going to acting classes.
I really enjoyed it - it was fun. I like getting into different characters.
The brothers on set
I've done lots of different characters. I used to like being funny, but now I like serious acting.
Darren is probably my favourite character so far.
I like him because he's a character who is going through a hard time. It's a challenge for me.
To act upset, I think of something that upsets me - like bullying.
Before filming, I normally need a minute or so to get into the mood.
Being on a film set can be boring at times because there is a lot of waiting around.
My real-life little brother, James, plays Darren's brother in The Worst Thing Ever, so he's usually around in my breaks.
When I am on set and doing stuff, I really like it!
I've done a couple of adverts before and I go to acting classes on Monday nights.
I'd love to carry on acting, but - whether I will or not - I don't know."