Emily Blunt is reportedly planning to marry next month.

The 'Devil Wears Prada' actress is busy finalising her nuptials to actor John Krasinski - who stars in the US TV version of 'The Office' - with the big day set to take place in either London or Los Angeles.

A source said: "They'll get married in about a month.

"She is planning the wedding right now and is down to the last-minute details. They picked up their wedding bands yesterday (13.04.10).

"It will be a big wedding. probably in London or Los Angeles."

However, the British beauty is yet to decide on her wedding dress and has tried on several designer gowns.

The source added to E! Online: "She looked at Monique Lhuillier and Vera Wang. She is definitely considering Monique Lhuillier."

Emily and John - who began dating in November 2008 - announced their engagement last August but didn't give any details about the proposal.

The couple have been extremely tight-lipped about their romance, even arriving at the Screen Actors Guild Awards separately last January.