Serena Williams & Common -- BACK TOGETHER?? ... Exes Hang at Post-Oscar Bash

You don't let just anyone hold your Oscar ... which is why it was very interesting when Common let his ex-GF Serena Williams carry his statue around last night ... fueling rumors they could be back on.

The two were spotted together at the Vanity Fair post-Oscars bash -- and even took a photo together (which Serena curiously posted and then removed from her Instagram page).

It's especially interesting ... considering that Common has been very open about how much he cared for Serena when they were together -- and even said he thought about marrying her.