Olivier Sarkozy and Mary-Kate Olsen

It's always good to get your twin sisters approval on dating and Ashley Olsen has given a thumbs up to Olivier Sarkozy, she approves of her twin sister Mary Kate's unlikely romance and new boyfriend.

The pint-sized fashion designer was spotted tagging along for a lunch date with her sister Mary-Kate and 42-year-old Olivier - the half-brother of former French President Nicolas Sarkozy - in New York City last weekend.

The group was seen dining at upscale Italian eatery Sant Ambroeus in the city's trendy West Village.

The 25-year-old former 'Weeds' actress has been dating French-American banker Olivier for almost seven months and the couple are rumoured to have officially moved in to his plush new East Village townhouse together recently.

According to city documents filed on September 10, Olivier purchased the 5-story love nest on August 2 after selling his previous property for £5.2 million in February.

A source said: ''They are really, really happy. 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''.

© Bang Showbiz