The Pitch Perfect 2 star teamed up with Tumblr's #PostItForward campaign, which strives to end the stigmatization of mental and emotional health issues and promote "positivity and support in online communities," according to Cosmopolitan.
Brittany, who has talked about her own past issues with internet bullying, admitted in a Tumblr video that she's gone through some times in her life where she's felt "different and alone," adding "for many years when I was younger I let negative things people said about me really affect my life."
"What I've learned is that it's really important to find the right support network and to focus on the positive things in your life and quiet that negative voice in your head," she continued. "The advice I give to people who feel different or are struggling is to simply tell yourself in your head 'maybe that's not true."
For the campaign, Brittany, and other celebs like Pete Wentz and Jordin Sparks are asking people to share their stories of internet bullying and how they overcame it with the hashtag #postitfoward on social media.