Miley Cyrus & Kaitlynn Carter Pile on the PDA at the VMAs!

For many, the news of Miley Cyrus' split from Liam Hemsworth didn't come as much of a shock.

After all, these two had broken up several times in the past, and their marriage seemed to be one long rough patch.

But while we were all pretty jaded about Miley's marriage, the speed with which she moved on still came a quite a surprise.

Within hours of her separation announcement, Miley was making out with Kaitlynn Carter on Instagram.

So not only was it surprising that she moved on, it was surprising that she did so with a total Z-lister.

Kaitlynn is best known as Brody Jenner's ex, and it seems she also had no problem leaving her previous relationship in the rearview.

But hey, this is Miley, many fans reasoned. She's probably just doing it for attention or acting out so as not to have to process her pain, right?

That theory has gone out the window in recent weeks, as it now appears that Miley and Kaitlynn are dating.

Like, dating dating.

Like, the two of them attended the 2019 VMAs together last night, and onlookers say they spent the night packing on the PDA.

"They looked very much like a couple," one witness tells Entertainment Tonight.

The source says that the two spent much of the night holding hands, and at one point, Carter "put her hand on Cyrus' butt."

And the two of them definitely weren't just working the crowd for attention.

One insider says Kaitlynn was with Miley in New Jersey all week as she rehearsed her performance for the show.

"Kaitlynn was swaying at the side of the stage as Miley rehearsed 'Slide Away,'" the eyewitness says of their interactions earlier in the day, during rehearsal.

"Afterward, the two walked backstage, hugging each other."

Yes, it certainly sounds like Kaitlynn is more than just a publicity stunt partner.

Already, Carter has met Miley's mom, Trish Cyrus, and sources say the Cyrus clan is surprised -- and a little alarmed -- by how quickly the relationship is progressing.

There are concerns that Kaitlynn is using Miley for fame, but after a lifetime in the spotlight, we're guessing Miley is a bit too savvy to fall for something like that.

And besides, Miley recently got a tattoo tribute to Kaitlynn.

Relationship ink is always the kiss of death.

So whether you love this couple or hate them, it's a safe bet that their relationship is not long for this world.

Also a safe bet? Miley will move on within 24 hours of their breakup.