Thorne's revelation comes just after she shared photos of herself kissing an unidentified woman on Snapchat.
The former Disney star and her ex-boyfriend, Gregg Sulkin, announced they were calling it quits just a week earlier. The couple had dated for a year and a half, and bought a house together in February.
"After much thought and soul-searching, we have made the difficult decision to end our relationship," Thorne and Sulkin, 24, said in a joint statement to ET last Monday. "We will always love each other and have a deep respect for one another, as we have each grown to be better people because of our time together. Our schedules made seeing each other difficult, and we decided that for now this would be the best."
ET caught up with Thorne last year, where she dished all about filming love scenes with Patrick Schwarzenegger for their film, Midnight Sun.
"It was the weirdest thing I've ever experienced in my life," she revealed. "We're running these scenes and all of a sudden he puts his hand on my leg and I'm like, 'Your arm's around me. I really didn't see this for us, but OK. I'm going with it. This is cool.'"