It's been almost 40 years since tween actress Linda Blair terrified audiences worldwide as Regan, an adorable girl possessed by a demonic force in 1973's The Exorcist -- one of the most successful and enduring horror films of all time.

Before landing the coveted role of the cursing, vomiting, nightmare-inducing Regan in director William Friedkin's film, Blair was just another aspiring young New York-based actress, she told Us Weekly during a recent visit to our NYC headquarters.

"I was being developed to be in Disney movies! I was the Cinderella girl!" Blair, now 53, explains. "Nothing could prepare anyone for The Exorcist and that type of filmmaking," she adds of the intense shoot, which took about a year and a half. "Could you remake it today? No. We made a magic show. If you did it today in front a green screen, it wouldn't work."

After that movie's unprecedented popularity, the former child star admits it was difficult to escape from its notoriety -- and young Regan's shocking, blasphemous epithets, the head-spinning, the pea-soup vomiting.

"People are getting kinder," she tells Us of fans. "They've always been okay about it, but the judgment is gone, the prejudice is gone. Now it's like, 'Wow! Thank you for that.' It brings me some peace of mind and heart . . I am not the person that they thought I might be or wanted me to be -- however, it gives me a platform. Why not spread love back?"

To that end, the star now heads up the Linda Blair World Heart Foundation, an animal rescue and welfare charity based in the Los Angeles area. And just in time for the Halloween season, Blair is partnering with Readers' Digest to promote Be Afraid of the Dark, a scary music compilation available on CD and via iTunes, with proceeds going to her foundation.

Catch up with Linda Blair on all things Exorcist and what she's up to today in this video now!