Article continues below advertisementOver a month after Britney Spears was arrested for a suspected DUI in Ventura County, Calif., she has checked into rehab voluntarily, a source revealed.According to TMZ, she finally agreed to get some help. "She realizes she hit rock bottom," one source said. Article continues below advertisement'She's Taking It Seriously' Tap Here To Add Ok Magazine as A Trusted SourceSource: megaThe star was arrested in March. The outlet reported that part of the reason she's going to rehab now is because of her pending DUI case.