The `Pirates of the Caribbean` actress has got engaged to the Klaxons keyboard player, who she has been dating since April 2011, her representative has confirmed.
Keira`s spokeswoman said: "I can confirm that Keira is engaged to be married to James Righton."
No other details about the engagement are known at this time.
James recently moved in to Keira`s £2 million London home, which she bought following her split from long-term boyfriend Rupert Friend in December 2010.
A source said in April 2012: "Keira suggested the idea and he moved his stuff in a couple of weeks ago. They want to get a puppy. It`s all pretty serious."
The couple have also recently been house-hunting for a country home.
Keira - who is worth in the region of £30 million according to the Sunday Times Rich List - was spotted looking at estate agent details in a tea room close to where Johnny Depp bought a 13-bedroom mansion in 2011 to use as his UK base.
The 27-year-old screen beauty - who will next appear in romantic comedy `Seeking a Friend for the End of the World` - recently said she believes stars should keep their private lives to themselves.
She said: "I hate knowing too much when I`m going to the cinema and watching as a viewer.
"I don`t want to know that the actor has just gone through a divorce. I don`t don`t want to know that the person is an alcoholic. It just gets in the way of my pleasure of watching the character."