The pair stared opposite each as lovers (among other things) in the new Russian spy thriller Red Sparrow...
And we're guessing these Soviets are chuffed about their Union.
The Daily Telegraph claim that Jen and Joel are very much a pair with "rumours [of their romance] are swirling throughout Hollywood."
The Hollywood siren, 27, has been joined by the 43-year-old, across the globe promoting the big blockbuster - and onlookers can't help but notice that they seem to be very comfortable with one another.
"The co-stars are often seen having private moments, chatting and giggling together."
It's not the first time romance whispers have circulated the cosy co-stars.
NW were exclusively told by Red Sparrow insiders, "They totally bonded during filming and spent lots of time alone together rehearsing."
They explained while Jen wasn't single at the time, so their relationship was more of a friendship.
Jennifer has since parted ways with her director boyfriend Darren Aronofsky, while Joel hasn't been with anyone since French model Dayan Reeves back in 2016.
"It was more of a friendship [at the time of filming] but since she's been single Jen's been inviting him over for dinners."
The NW insider also shared that Joel is completely taken with her.
And he's not hidden that, voicing his praise for his co-star.
Chatting to the HeraldSun, Joel gushed, "Jen's a machine. She's up for anything and (is) game to wrestle with whatever demons she needs to for the sake of the movie."
Both stars are currently single.
This isn't the first time the Hunger Games beauty has been rumoured to be dating a fellow actor.
She was infamously linked to then-married Passengers' co-star Chris Pratt.
Jen spoke to KIIS FM, shutting down any allegations made against her.
"I never had an affair with Chris Pratt on Passengers. That's a good one."
"I mean they got a divorce like two years later and everybody was like [shouting] Jennifer Lawrence! And I was like what the… what I'm in Montreal two years later."