Sian Diamond will be leaving Waterloo Road later in the series.
The news follows the announcement that Daniel Chalk will leave.
Sian will leave during the second part of Series 8 (Episodes 11-20). Also leaving are Scout Allen and Jade Fleming. Josh Stevenson, already announced to leave will film a guest appearance.
Meanwhile, Nikki Boston will return to the show during the second part of Series 8.
Jaye Jacobs, who plays Sian Diamond, originally joined in the second part of Series 7.