Sprouse's account was attacked first on Monday, suddenly displaying explicit tweets referencing the actor's time on the Disney Channel.
After Sprouse was hacked, Reinhart tweeted, "Cole's Twitter has been hacked BTW. F— people who do that, seriously."
Cole’s Twitter has been hacked BTW. Fuck people who do that, seriously.— Lili Reinhart (@lilireinhart) August 14, 2018
The tweets have since been deleted from Sprouse's account.
On Wednesday, Reinhart's account was targeted, seemingly by the same people who hacked Sprouse.
"Shouldn't have talked s— about us, here's to lili fans found this masterpiece in iCloud," one tweet read.
An explicit photo was also posted with the tweet, but it was determined by The Blast to be of an adult film star and not Reinhart.
The photo and tweets have since been removed from the actress' account, though it's currently unclear whether she has regained control of the platform.
Back in June, Sprouse seemingly predicted the hack, tweeting, "The point is to establish a strange enough twitter that if someone hacks your shit it would just look like business as usual."
The point is to establish a strange enough twitter that if someone hacks your shit it would just look like business as usual.— Cole M. Sprouse (@colesprouse) June 3, 2018
Sprouse and Reinhart have been rumored to be dating for years, and have neither confirmed nor denied their relationship.
For Sprouse's recent birthday, Reinhart shared a touching tribute on Instagram, posting a photo of the actor along with a heartfelt caption.
"It seems as if the world would still be a stranger to me, if not for you," the 21-year-old wrote. "I'm so thankful that our paths intertwined to form this beautiful adventure~ Happy birthday, my love."
In July, Harper's Bazaar published an interview with Reinhart during which she explained that she wants to keep her personal life private.
"I'm not okay talking about my relationship," she said. "I'm not going to tell you my love story. That's just not appropriate right now."
"I don't act to be famous," she continued. "I just am a performer."
Reinhart added that the aspect of her current life she's had the most trouble adjusting to is "the speculation."0comments
"Am I pregnant? Am I dating someone? Am I gay? Am I gaining weight? Am I homophobic?" she said. "People will always have something to say. I've accepted that. It doesn't mean it's not frustrating when people say those things. It's not like it just rolls off my back."
Photo Credit: Getty / Kevin Mazur/Fox