Bella Thorne is in a polyamorous relationship.

Bella Thorne

Bella Thorne

The 21-year-old actress has been romancing singer Benjamin Mascolo since April this year, and has now revealed they've welcomed a third party into their relationship, as they are now both also dating Alex Martini, who works as a production assistant on movie and TV sets.

Bella announced the news as she took to Instagram to share a picture of herself cuddling her new girlfriend, although Alex's face is hidden in the images.

The 'Famous In Love' actress wrote alongside the picture: "She's very cute. first girl I have dated that's camera shy (sic)"

Benjamin then commented: "You girls are cute", and Bella replied: "see u soon baby", alongside three heart emojis.

Meanwhile, Bella recently revealed she identifies as pansexual, after initially coming out as bisexual on social media in 2016.

She said: "I'm actually pansexual, and I didn't know that. Somebody explained to me really thoroughly what that is.

"You like beings. You like what you like. Doesn't have to be a girl or a guy or a he or she or they or this or that. It's literally you like personality. You just like a being."

And the new addition to the romance comes after Benjamin, 25, previously joked he hopes Bella invites another woman into the bedroom.

He said earlier this year: "My girlfriend is bisexual. Some of you might think I am lucky boy because of that. Well, I think I will consider myself lucky the day there will be more than one person in bed with me."

However, at the time he wasn't convinced about bringing a third party into their relationship, because he said he was a "jealous" person.

He added: "I am a very jealous person and since she is bisexual it is even harder for me now."