Twitter. It’s not just a social messaging service but a battleground! Rihanna got into a 140-character feud with thoroughly plastic surgery-ed comedienne Joan Rivers after Rivers was aghast at RiRi’s confession to Oprah (that she still loves her abusive ex Chris Brown). Now, Rivers’ ‘Fashion Police’ co-star has thrown her opinionated and outspoken self into the mess. Which side did Kelly O. take?

We’ll tell you in a sec, but first, a refresher course for you: Ri balled to Oprah, claiming she still loves Brown and always will, despite the fact that her face met the business end of his fist back in 2009. Rivers tweeted: “Rihanna confessed to Oprah Winfrey that she still loves Chris Brown. Idiot! Now it’s MY turn to slap her.” Ri replied, insinuating that Rivers was old and not with it. She tweeted: “@Joan_Rivers wow u really do get slow when you’re old huh?” She also told her to slap on some diapers.

Ouch!

Rivers took it in stride, writing: “@Rihanna, everyone knows: If he hit you once, he’ll hit you again. Read the statistics. PS – Love to have you on Fashion Police!” Always the opportunist, that Joan!

Now, Kelly O. dropped a tweet into the mix defending Rivers, even though her co-host already tried to smooth things over with RiRi. Perhaps Kel should have left well enough alone? Her tweet is below.

Watch the Rihanna ‘Where Have You Been’ Video