The Lovely Bones star received critical acclaim for her Oscar-nominated performance in 2007's Atonement and is tipped as one of Hollywood's most promising young stars.
But the 15 year old is already discovering the downsides of fame - she has walked away from school over her teachers' and fellow pupils' negative attitudes towards her.
Ronan, who now has lessons at home, tells the U.K.'s Guardian newspaper, "The reason was teachers giving me a hard time. Teachers and students. Some of the students were, you know, mean. But I only stayed a while. It wasn't really working out. You know, the school is a good school and the people who go there are good people. But when your schoolmates recognise you before they've met you, and the teachers do, too, it can make things very awkward and difficult. It's a shame."