The Atonement star admits she was stunned when the Because The Night hitmaker turned up at the New York premiere of her film The Host to check out her work, and even more surprised when Smith asked to be introduced to the teen.
Ronan reveals the singer shared "these amazing words of wisdom" about life in the spotlight and then followed up their chat with a sweet email on her 19th birthday in April (13).
She tells The New York Times Style Magazine, "Out of all the people I've met through showbusiness, she's the most incredible, such a generous and kind and intelligent woman."
And Smith insists the admiration is mutual: "I've just been captivated by watching her. She has a certain inner sincerity that comes out and magnifies her character. She's so gifted. I enjoyed meeting her so much. She is very singular. I mean, I don't think she's innately fragile. I think she's very strong."