During a Thursday interview, the singer dropped the news on Ryan Seacrest.
"He's my boyfriend. It's new and it's fun and it's nothing too serious," she said. "I don't want anything that's going to take up so much of my energy and time right now in a bad way. I just want to have fun and that's what it's about."
Kemp, 25, is an outfielder for the Los Angeles Dodgers and seems to have a gaggle of female followers on his Twitter account. But his exploits have also landed him in trouble. When he was 17, Kemp and four other young athletes were named in a rape complaint, according to CNNSI. No charges were ever filed.
Last summer, Rihanna's ex, Chris Brown, was sentenced to 1,400 hours of "labor-oriented service" for brutally attacking Rihanna. Brown is also under a restraining order, which prevents him from coming near Rihanna until 2014.