The former Bachelor contestant shared a pic of herself holding up a peace sign and making a kissing face for the camera.
"Damn, looks like I needs [sic] to write a book," she quipped alongside the pic, seemingly alluding to Hannah's upcoming memoir, God Bless This Mess.
"Book coming 2022. Maybe 2023," Kelley joked.
Peter broke up with Kelley on his season of The Bachelor before the hometown dates. He went on to get engaged to Hannah Ann Sluss, though they broke up shortly thereafter.
Like Kelley, Hannah Ann seemed to address the news of Peter and Hannah's hook-up, taking to TikTok to share a video of herself putting on lip gloss as she mouthed the words, "That was embarrassing. I really hope you're embarrassed. Wow."
"When the tea officially spills..." Hannah Ann wrote alongside the clip, which she captioned, "Always trust your instincts ladies."
As for Hannah, she first met Peter when she was leading The Bachelorette. She sent him home just before the finale, and got engaged to Jed Wyatt. That relationship ended, and it didn't end up working out with her runner-up, Tyler Cameron, either.
Then, Peter became the Bachelor. Hannah appeared on his season twice, once during the premiere to wish him well, and again to host one of his group dates. It was during that second appearance that Peter offered to quit the show for her.
Eventually, his season wrapped filming, and his relationship with Hannah Ann was quick to fizzle. Then, as his season of The Bachelor was airing, Peter got invited to Dylan Barbour and Hannah Godwin's engagement party, and was eager to go when he learned Hannah Brown was going to be in attendance.
"I see Hannah Brown walk in. She's got this beautiful dress on. The first thing you see is that big, beautiful smile. I was like, 'Phew. Alright. How is this gonna go?'" Peter recalled on his Bachelors in the City podcast. "... We end up chatting or whatnot. We have to do this in secret, because no one can know about anything."
Peter left the party, but soon circled back for Hannah. The pair had "a good talk" on the drive and eventually ended up at Peter's house, where they slept together.
"The chemistry just wasn't there," Hannah told People of the encounter, a statement that Peter agreed with.
"It just really wasn't fully there, I guess," he said. "I agree with what she said. It wasn't the same as we originally felt, but nonetheless it was great to talk."
Afterwards, Hannah found out that Peter "had another girl on his mind." That girl was Madison, who he went on to briefly date after his season finished airing, and before getting together with Kelley.
Shortly thereafter, the pair texted for the final time, though they're not on bad terms.
"Things might not have turned out the way I expected, but I try to learn from every moment," Hannah said. "I don't wish ill on anybody. And I'm in a really good place."
"Nothing's bad. Nothing's spiteful. Nothing's mean or anything like that," Peter agreed, noting that he'd "love" to get Hannah on his podcast. "... Hannah is one of the most amazing people I truly have ever met... She's a good, good person. A good, good heart.... Obviously, I wish her all the success and all the support."