JoJo achieves a difficult balance: The songstress manages to combine the voice of an angel with the mouth of a sailor.

She may have cleaned up her act when performing 'Marvin's Room,' but her potty mouth returned on Oct. 24. The songstress performed an acoustic cover of Rihanna's 'What's My Name' at the Hard Rock Cafe in Baltimore and dropped an f-bomb.

JoJo, on a free tour to benefit breast cancer awareness, will make stops at seven Hard Rock Cafes. Perhaps she feels more comfortable cursing now that she's wrapped her tour with Joe Jonas and has more mature audiences than before.

JoJo's next album, 'Jumping Trains,' is slated for an early 2012 release. With a voice like hers, JoJo shouldn't worry about anyone forgetting her name anytime soon.

Watch JoJo Cover Rihanna's 'What's My Name'