Ricci McLeod and Dominick Baron play Brendan and Terence Gilcrest
Ricci McLeod has loved being part of a big extended family for his role as Mary's eldest son Brendan.
"I'm an only child, so having brothers and sisters is completely new to me, but it has helped me to find out what it's actually like," says Ricci, who was 16 when he made his television debut on William And Mary, and is 19 now.
"It's all quite strange, all of a sudden I've got a step dad, a brother, two half sisters, a half brother. Dominick, who plays Brendan's younger brother, has become like a real little brother, and I look out for him."
Ricci says he couldn't wish for better screen parents.
"Martin is so great. He's fun, and he helps me with my lines. And Julie is wicked! She's brilliant. She so easy to talk to."
Ricci had two big passions at school: acting and football and he would love to find a role where he could combine the two.
"I would love to do something in acting that involved football.
I was lucky in a way because I did a film after William And Mary
called The Football Factory.
But that was about football hooliganism. I'd love to be able to show off my football skills on television.
Ricci is working on a new Channel 4 drama series called Ghost Squad.
Dominick Baron plays Terence, Mary's youngest son, who takes up a new hobby that puts his life in danger in the new series.
"Terence goes through a lot in this series. He gets involved with the wrong people, and gets into tagging, which leads to him getting beaten up by a rival gang. I think it's something that goes on a lot in real life, and it was good to portray because there was a lot of action.
"I'd never get involved with something like that. The only similarities between me and my character are that we're a similar age and we dress the same as well. We are both a bit 'street'.
"I live at home with my mum so things are quite quiet compared to the crazy William And Mary household. I think I prefer my own home life because I can chill out more there and watch what TV I want!
"Julie was like a mum to me on and off set. We really clicked and made each other laugh which made doing scenes with her really easy and fun. She even met my mum and they get on really well now."
Dominick attended the Anna Scher school. He has appeared in Casualty and Little Big Mouth.
He is now concentrating on his schoolwork, in preparation for his GCSE's.