Here, newcomer Harry Reid - who has taken over the role of Ben - chats about joining EastEnders and what fans can expect from the new storyline.
How is Ben when he comes back? Is he a reformed character?
"Ben has come back knowing what he left behind. He wants to try and bury a lot of the bad stuff that happened and wants people to have a good view of him. At the same time, he doesn't want to be weak - he is still a Mitchell and Phil's son. He wants people to understand that he's smarter now, whereas before he was a bit of a loose cannon.
"Ben has been inside twice and that has a lasting effect on people. He's got a bit of a brain now, so it will be interesting to see how he starts to manipulate people in certain ways. There is that element of nice about him, and he's half Beale so he still has a soft side as well."
Is Ben still hot-headed?
"He's still got that explosive temper and a lot of it is frustration. He wants people to forgive him, but he knows it's not going to happen. That's where the frustration comes from. There's still going to be that explosive element, you won't be able to take that out of him, but it's more how he controls it which will interest people."
How do things go between Ben and Phil?
"Phil's happy that Ben's back but it's not that simple. When Ben left, he said he didn't want to see Phil whilst he was inside - he wanted to do it by himself. It was a personal thing for him, as he wanted to believe he could get through it himself.
"Ben has always relied on his dad and Phil has always had to back him up, but the Mitchells are about strength and what you can do as a person. Ben going back to see Phil is really about having someone by his side after he's been gathering his thoughts for so long."
How does Ben feel about seeing Shirley again?
"Ben loves Shirley. He's not had a good life with women in terms of motherly figures. He loved Heather - her murder was an angry reaction and an accident. What hurts Ben the most is he knows that ultimately, it's his fault that there's a chance that Shirley will never forgive him because of what he did.
"Shirley has got to bring herself to forgive him. If you put yourself in her position, it's hard. Ben's not scared to see her, but he's scared of what the outcome will be of their friendship. That's what he wants back - their friendship."
Why has it taken Ben so long to come back to Walford?
"At first, Ben didn't think it was a good idea at all. It's Jay who has persuaded him. I think Jay feels safer with his brother, although even they have their comings and goings. He's been waiting for his moment to come back when it feels right, feels necessary, and when it makes a big impact as well."
Will there be any relationships for Ben?
"He's discovered over the years that relationships can cause a lot of problems. I think it would be nice for him to get a relationship, but I think it's difficult. People know who he is and what he's like. He doesn't trust anyone. He only trusts himself. It will be interesting to see how he goes about with that."
Will Ben find it difficult seeing Lola and Lexi?
"I think so. The problem with that is he's not been around at all while Lexi's been growing up. That makes it even more difficult for a young dad. Ben is 18. He's got to try and support her, a kid, and that is a difficult thing. He also knows that what happened between him and Lola shouldn't have done. It was only because Ben wanted to confirm whether he was gay or not."
Does Ben want to wreck Phil and Sharon's wedding?
"No, but he wants Phil and Shirley to be together because he knows they love each other - they've been through thick and thin. Ben loves Shirley, and Phil loves Shirley. He knows that it is the perfect relationship.
"He's never met Sharon but he's heard things about her from Peggy and Grant and all they say is that she split the two brothers up. There's no debate in that. Ben wants his dad to be happy, but he doesn't want to feel unwelcome. Sharon, obviously, doesn't want him there. Hopefully, through persuasion, Ben can get her to drop her guard."
What can we expect from Phil and Ben's relationship?
"You can expect them to be united together. Phil will always back his boy as long as his boy proves himself. Although Phil loves Ben, you have to prove yourself in this family. Ben will be going out to prove to his dad that he is a Mitchell and that he's smarter now. He will be proving to Phil that he is worthy enough to be in the Mitchell family."
How daunting was it filming those initial scenes with Steve McFadden?
"I was bricking it. Steve's quite intense, as you can tell by his character and he's being doing it for years. It's different to come into this with other actors as a whole family because you can latch on to others, but by yourself, it's a big bit of pressure. Steve's kind of adopted me in a lot of ways, like a father/son thing outside of the scenes. He's helped me a lot."
What advice has Steve given you?
"To take each page as it is. Before I came here I was thinking, 'I'd better learn all these lines and get them all in my head' Steve said it's about what's on the page, it's not a memory test, it's not live. You read the page and it's all about the truth and what you can get out of it. It's not theatre, it's not theatrical, it's dramatic in its own way but it's what's on the page."
What was your first day like?
"It was quite intimidating and my first week was one of the scariest weeks of my life. Multi-camera as well was a whole new ball game. There' a camera here, a camera there, and I can't move there, because he'll see me, and it's just takes a lot.
"Danny Dyer came up to me, and the man's done however many films and he said, 'It takes a while, mate. You'll get into it'. Everyone's been brilliant and so inviting and it's made me feel comfortable to just get on with it."
How do you feel about the attention that comes with a role on EastEnders?
"Steve said that my world will change and it will be very different. What I've gathered is to be yourself and make sure that you're still the person that's here today, so I'm not going to be a different person in years to come. Everyone deals with it in their own way. People ignore it, people lap it up, people stay the same. You can deal with it any way you like."
Have friends said that you look like Ben at all?
"I have blue eyes, like Steve, and the glasses kind of help. I didn't wear them at my audition actually because I didn't want to come across like, 'Look, I'm Ben, glasses and everything'. A lot of people have said that I look like him, and there are similarities, I'm just a bit older."
How did friends and family react when you got the part?
"I had to keep quiet for a month which was difficult. My Scottish nana ended up having it announced on the supermarket tannoys in Scotland! That was interesting! My family took it brilliantly though - they were really chuffed. My mum still finds it weird that she'll be watching EastEnders with me in it. It doesn't feel real yet because it's not on screen."
Where do you plan to be when it goes out?
"My mum wants to do a cinema night and watch it. I did say to her, 'I'm not going to be in it long in the first one. It might be a bit of a waste of time!' I'd have to invite everyone in at the last minute - 'Get in now!' So I plan to be there, but I might be working anyway. Hopefully I'll be at home, so she can pop open the champagne and give me kisses and all that!"