Who would be perfect to play Aly Michalka’s sister on Hellcats? How about her actual sister AJ? The other Michalka will join the series on Tuesday as Deirdre, a girl Marti meets while searching for clues about her father.

Marti Perkins (Aly Michalka) will find Deirdre at a record store and eventually put the pieces together to make the connection that they’re actually sisters. The revelation leads to some heartbreaking information about Marti’s father. Aly and AJ co-starred together in Disney's Cow Belles, and they front a musical duo named 78violet.

New episodes of Hellcats return to The CW on Tuesday nights.