YOU's Shay Mitchell says Peach is a 'complete 180' from her Pretty Little Liars character

Shay Mitchell is very familiar with the dangers of the internet. Or at least her characters are. After all, her Pretty Little Liars character Emily Fields (and her friends) were cyber-stalked on the show for seven years. And now, another of Mitchell’s characters will find herself involved with a stalker when YOU premieres.

YOU, which is based on the 2014 novel by Caroline Kepnes, follows Joe Goldberg (Penn Badgley) as he falls for — and stalks — a young woman named Beck (Elizabeth Lail). Then there’s Peach, Beck’s (very wealthy) best friend, played by Mitchell. And let’s just say that Peach is not the biggest fan of Joe.

EW talked with Mitchell about her post-PLL role and what Peach loves about Beck.

ENTERTAINMENT WEEKLY: Peach is so different from Emily, your Pretty Little Liars character. Was that part of the appeal?
SHAY MITCHELL: Yes, Peach was just this fun, juicy character. To some, she could just be considered as a bitch, but I saw many different layers to her. She does have such a love for Beck. I also just loved her character so much and haven’t played anything remotely close to her. So it was fun to go from playing nice, sweet Emily Fields for seven years to the complete 180 in every way.

Peach’s wardrobe could not be more different than Emily’s.
Oh ya! It was funny because I knew that I was going to be moving to New York for three months to shoot YOU and I brought all my clothes, literally nine suitcases of stuff because it was also fashion week. And the costume designer [on YOU] really let me work with her. I actually put in a lot of my clothes and my bags into the character, so it was fun to really get to dress her up and pay attention to what she wore. Peach wears heels, and if she’s in flats, they’re Juicy loafers. [Laughs]

How do you generally describe Peach?
Peach is your typical Queen Bee. I think her upbringing was very lonely. She was offered a lot of materialistic things but as far as love from parents and family, do I think she had that? No. I think it’s made her cold as a person and I think that’s why her love for Beck is so strong, because Beck is the complete opposite of what Peach is. She’s this lovable, light-hearted poet and Peach envies that in a way. She wants to be around Beck as much as possible. She’s had a little bit of a difficult upbringing and she definitely has some high walls built up around her, but deep down I do think that she truly does care for Beck and she is a good person. She just doesn’t really know how to not be so blunt about things. [Laughs]

In the book, we mostly see Peach in relation to Beck. Does that also ring true in the show?
It is similar to the book in that regard. Peach is a supporting character and you do see how her love for Beck isn’t the best when it comes to her meeting Joe. I almost want to call it a love triangle, the relationship that Beck, Peach, and then Joe have when he’s introduced into the picture. Neither Peach nor Joe is quite happy about it.

Both YOU and Pretty Little Liars contain an element of mystery. Is that something you think you’re drawn to?
I do, but I feel like this is a tad bit more realistic. Some of the things that happened in PLL were way out there, and I love that. But I also like the realism that takes place in YOU and I think the viewers will appreciate that.

Does this show have you thinking more about social media and what you put out there?
The interesting thing about this story is that it’s not just about a stalker, because you question some things. I question things that I’ve done, that my friends have done, stories I’ve heard from people about how far you’ll go to get to know somebody before you even meet them. With the internet, you can hear someone’s voice, you can see what their style is like, you can see what their family looks like, you can find out so much about somebody before even meeting them. That’s essentially what Joe is doing at the beginning [of the series]. He’s using the information that’s available to anybody and I think that’s the thing that we all have to remember: A lot of the stuff that he’s finding out about her is very Google-able. Sometimes we forget how much we really put out there.

YOU premieres Sunday, Sept. 9 at 10 p.m. ET on Lifetime.