The blonde beauty, who is currently filing the new adaptation of Annie in New York City, in which she both sings and dances, is already following 49 people, including her close pals Leonardo DiCaprio, Drew Barrymore, Christina Aguilera, Gwyneth Paltrow, Lake Bell, Jessica Alba, Reese Witherspoon and Jason Segel.
Cameron, who previously dated Justin Timberlake, isn't expected to reveal too much about her daily life on the micro-blogging site, as she is very aware of what she says about herself in public.
She previously said: "I'm very aware of my words and who I say them to. I'm aware that what I said gets overheard, and people can take it and twist it, and I have no control over that."
- BANG! Showbiz