The two were spotted getting hot and heavy with each other over the weekend at a Halloween party at Seth MacFarlane's house.
"They showed up together and made no effort to hide that they're back together. They were stealing kisses throughout the night, holding hands and just seemed to enjoy being together."
They wouldn't leave each other's side the whole night and "Demi couldn't seem happier about it!"
And despite what they're telling people, they were DEFINITELY acting like a couple! The witness added:
"They were dirty-dancing to the music, and when they were seated, Wilmer had his hands on Demi's knee the entire time. He was being very boyfriend-like and affectionate."
Whatever makes her happy makes us happy! Just don't break her heart, Wilmer!
[Image via WENN.]