Saoirse Ronan is "phenomenal", according to her Hanna co-star Olivia Williams.
The Irish actress, who plays the title role of a teenage soldier, impressed Olivia greatly after they acted in scenes together for Joe Wright's action thriller.
"I was all ready to go, 'Who does this young girl think she is?' but then I did one scene with her, and she just blew me away - she's a phenomenal actress," Olivia said.
While the 42-year-old, who's currently starring in the West End play In A Forest Dark And Deep with Matthew Fox, didn't disclose her character, she also enjoyed working with director Joe, best known for his work on Atonement and Pride And Prejudice.
"He is fantastic. He is really amazing and gifted, a visionary man and so extraordinary," gushed Olivia.
Hanna, which also stars Cate Blanchett and Eric Bana, is released on May 6.