Keira to wed her rocker.
The 27-year-old Pirates of the Caribbean star has been dating James Righton, keyboard player with indie band Klaxons, for about 15 months.
The couple were introduced by their mutual friend, TV presenter Alexa Chung.
Aides to Keira confirmed the engagement but refused to say any more. The star is fiercely protective of her privacy.
Keira, who starred in the first three Pirates movies as well as Atonement and Pride and Prejudice, previously dated actor Rupert Friend and Irish model and actor Jamie Dornan.
She is due to play a wannabe singer in Can a Song Save Your Life? London-based Klaxons won the Mercury Prize in 2007 for debut album Myths of the Near Future.
The band released their second album in 2010 and are working on their third.
WE DO* Keira and James