The singer, who turns 30 this month, shared her painful past with the December issue of Los Angeles Confidential magazine.
The singer-actress says she drew on her experiences of being bullied while working on her debut movie, Burlesque.
'I tapped into that young, naïve little girl with big, wide eyes that came into this world of very jaded, sometimes bulldog personalities and had to find inner strength and fight to be heard many times…' she says about her character Ali, who moves to LA to fulfill her dream of becoming a burlesque dancer.
'I definitely had to tap into that place, but it's right underneath the surface for me because I was bullied all through school – since I was seven years old – because of my love and passion for what I did.
'I definitely felt alienated many times in my life, so I had a lot of experience with pain and hardship and having to fight through that.'
Aguilera co-stars with Cher in the new film, but says that as a little girl she wasn't allowed to watch the legendary singer's music videos.
She tells the US magazine: 'Cher is no joke! She's a force to be reckoned with.
'When I was a little girl, I was never really allowed to watch videos of Cher or Madonna because they were a little risqué – and then, of course, I grow up and I'm wearing chaps in my Dirrty video. Go figure.'