Mary-Kate Olsen is moving in with boyfriend Olivier Sarkozy.
Olivier, 42, is buying a townhouse in New York and although they won't officially be living together, 25-year-old Mary-Kate will be there most of the time.
A source told the New York Post newspaper: ''They are really, really happy. And Olivier is buying a townhouse below 14th Street, to be with Mary-Kate. We are told they're not officially moving in together - they both think it's too early for that. But he's telling friends that Mary-Kate is the best thing that has happened to him in a long time.''
Mary-Kate previously dated artist Nate Lowman for over two years before splitting in 2010, while Olivier romanced actress Stella Schnabel for a year before their break-up in March.
Olivier was previously married to wife Charlotte and they have two children together.
Charlotte has since called the coupling ''grotesque'' and ''not right''.