Keira Knightley does not believe that she is "guaranteed" a successful career.

The 26-year-old actress is currently filming British director Joe Wright's adaptation of Leo Tolstoy's classic novel Anna Karenina.

Although Keira has received numerous accolades for her work, she does not take her professional choices lightly.

"If you're offered the work, you should take it," Keira told British newspaper The Independent. "Within the profession I am in, there is no guarantee of anything. You can make three wrong choices and all of a sudden, the parts dry up."

Keira takes her craft very seriously. The actress has been affected by what she reads about herself.

"As an actress I need to be emotionally available," Keira explained. "There have been many occasions [where] I just sit on the bathroom floor and burst into tears. Then, there are other days when you go, OK, it just doesn't matter [what they say]. That's fine. I think it depends on the day of the week really."

Keira is not a fan of speaking about personal matters in public. She prefers to keep emotional affairs to herself.

"I think everybody has the right to a private life," Keira declared. "The line is actually quite clear. When you do interviews like this, you present a piece of work, talk about it and hope that maybe the journalist is interested by it in the same way that you were interested by it and maybe the public will be interested, too."

Anna Karenina starring Keira and Jude Law is set to be released late this year.