Ashley Tisdale has signed on to co-star in her first regular broadcast series show ‘Hellcats’.she will play as Sierra, the peppy and fiercely intense captain of the Hellcats who, after an initial clash with Marti (Aly Michalka), her new roommate, realizes that she just might be the godsend the Hellcats need to win the championship,Hellcats follows Marti, a college girl from the wrong side of the tracks who, after losing her scholarship because of budget cutbacks and her mother’s (Gail O’Grady) chronic irresponsibility, joins the Hellcats, the college’s competitive cheerleading team.TSR Report.