For the past two years, Serena Williams has been linked to an on-and-off romance with her coach, Patrick Mouratoglou. As complicated as his relationship with the Frenchman can get, the love affair of the 19-time Grand Slam winner can become even more complex with his ex-boyfriend, rapper Common, apparently trying win her back again.

Fresh off another Grand Slam win at the Australian Open in January, the 33-year old Williams hit the red carpet Sunday night at the after-party of the 87th Academy Awards. And Guess who she was with? It's no other than her former boyfriend Common, who won his first Oscar trophy for his contribution in the Academy Award-winning single Glory (Best Original Song).   

Paparazzi site TMZ provided more juicy details on Serena-Common 'reunion' at the 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.

Common, who also had previous romance with singer Erykah Badu and actress Taraji P. Henson, confessed in an interview with the Breakfast Club last year that his relationship with Williams was serious to the point he almost tied the knot with the tennis player. Thing unfortunately didn't go out well between them in the long run, but their latest photo together might be a sign they are trying to rekindle old feelings.

As for Mouratoglou, Williams already cleared that his connection with the French tennis coach was nothing but professional, although some of their pictures together - like the one that went viral last January - would suggest otherwise.