United Kingdom, Aug. 23 -- Dame Helen Mirren finds starting a new job to be a "nerve-racking" experience.

The 80-year-old actress has enjoyed huge success in her career, starring on stage and screen for more than six decades - but Helen still feels anxious whenever she begins a new role.

She told People: "I think it's because every project that you go into is an unknown.

"And each time you enter into a new project, you never know how it's going to be or how the people are going to be and whether the chemistry will be good or a disaster. So stepping into a project is nerve-racking."

Helen acknowledges that every role is a new and unique challenge.

The veteran actress explained: "Every single one is completely different and has a diffe...