Selena Gomez says she's not dating Niall Horan, even though they left the X Factor UK party together. And now reports are swirling that they were all over each other at the party! Apparently, they snuck into the fête together through a side door, and were totally making out.

“They spent the entire night locked together and were very touchy-feely. They kissed in a corridor. There is no doubt there is something going on between them," a source told The Sun.

At this point, we demand pics!

Do you think that Niall and Selena are keeping their relationship hush-hush? Should they date? Let us know in the comments!