But have they taken things to the next level already?
After Mod posted an intimate photo kissing Bella's stomach on Instagram, fans have speculated whether or not they're now expecting a child.
He wrote, "ur doing so amazing I️ love watching u shine bb."
Comments instantly started flooding the photo, with fans asking about a possible pregnancy.
What's interesting, is that Bella just cancelled a whole bunch of promo interviews she was meant to conduct for her new movie Assassination Nation, as she was reportedly "sick".
"She called in sick for most of her press interviews on Monday. She canceled everything in the morning," a source told Page Six.