The actress plays "troubled soul" Rhiannon, who launches a hate campaign against fellow pupil Scout.
"She's a real bully and does some truly terrible things to Scout, one of the show's best-loved characters. But I think it's obvious it's just a front and there are reasons behind her actions rather than her just going out of her way to be evil," she told the Western Mail.
"She goes on her own little journey to discover why she is the way she is, and that's exciting to watch. I'm proud to be involved in a storyline about bullying.
"It's an important issue to highlight and it's something that happens every day but which I feel people turn a blind eye to because it occurs so often.
"I just hope by watching me and my character people will realise how hurtful bullying is and anyone who is a victim of it will have the courage to speak up and get help."
Waterloo Road airs Thursdays at 8pm on BBC One.