Serena Williams and Common raised eyebrows by spending a lil time together at a small private event Friday night ... sparking speculation they might be dating again.
An eyewitness tells us Serena and the rapper/actor were in a back room chatting before she spoke to the audience at the grand opening of the Yetunde Price Resource Center -- for people affected by violence.
We're told the exes were careful to avoid taking pics together, but individually each got a photo with Compton's mayor, Aja Brown. They left in separate cars after the event.