Pretty Little Liars Pretty Little Liars

Is Hanna Marin going to betray her fellow Pretty Little Liars?

As we saw in last week's episode, Hanna is aware of her mom's financial struggles and she'll do just about anything to help out. Viewers got a glimpse of her former alter ego, Hefty Hanna, when the mysterious "A" told her to eat a box of cupcakes to get back some of Mrs. Marin's missing money. Ashley Benson tells us the demands will only get steeper.

Pretty Little Liars: The identity of "A," revealed — and other scoop for the new year

"'A' makes her do something really horrible against her will," Benson says. "She's helping her mom out and doesn't want to lose the house, so [she's] doing things she absolutely does not want to do but has no choice."

While the friendship among Hanna, Emily, Spencer and Aria has been what's kept the girls focused on their mission to find out who "A" is and if it's the same person who killed their friend Alison, Benson says it's only a matter of time before the strong ties begin to unravel.

VIDEO: What is Pretty Little Liars' Ashley Benson's type of guy?

"These next couple episodes for Hanna really test her friendship with the girls — especially one of them, in particular," the 21-year-old actress says. "[Hanna is] the one who's changed the most so far out of all the girls going from the popular, stuck-up, snobby girl to the down-to-earth girl ... This whole thing with 'A' is making that all go the other way."

Will Hanna reach her breaking point?

Pretty Little Liars airs Mondays at 8/7c on ABC Family.

Additional reporting by Natalie Abrams