It’s been four months since the world learned that Jennifer Aniston and Justin Theroux have ended their marriage.

But it seems that at least one half of the famous couple is having a little trouble letting go.

First, we heard reports that Jen was engraged by Theroux’s relationship with Selena Gomez.

Now, it seems she’s concerned about a different young starlet who may have caught her ex’s eye.

It seems Justin developed a close friendship with Emma Stone while he was still married to Jen.

Radar Online reports that in the months since Jen and Justin made their split public, he’s been spending a lot of time traveling the world with Stone.

And Jen — who reportedly was no great fan of Emma’s to begin with — is reportedly very, very unhappy about the situation.

“It bugs the hell out of Jen that Justin got close to Emma during their marriage and she isn’t taking this lying down,” a source tells Radar.

“She’s dragging Emma every chance she gets and warning pals like Jason Bateman and Jimmy Kimmel to avoid her.”

The insider says Emma has long been disliked by Aniston and her clique:

“Jen and her squad take issue with the fact that Emma never met a role she couldn’t steal from another actress [most famously ‘La La Land’ from Emma Watson],” she claims.

“I don’t think she realizes who she messed with and how far Jen’s reach is.”

That’s … pretty ominous-sounding stuff.

And apparently, Jen has a history of going medieval on women who incur her wrath:

“This is a pattern for Jen, never directing the rage or gossip at the guy who left her but instead at the next woman he hooks up with,” says the source.

“Jen is in revenge mode and Emma needs to recognize that she’s messing with somebody with a lot of loyal Hollywood friends.”

Now, Emma is an Oscar-winning actress and one of the most in-demand talents in Hollywood, so she’s probably not too concerned about the possibility that Jen will torpedo her career.

But it’s important to bear in mind that Jen’s been one of the highest-paid actresses every year since Emma was in grade school, and she still has serious clout in the industry.

That doesn’t mean she’s capable of crushing Emma like some sort of cartoon supervillain — but she probably make her life much more difficult.

Maybe Stone should just find a more drama-free relationship.

We hear Brad Pitt’s available!