Saoirse Ronan celebrates her 20th birthday with Bridesmaids themed bash

The Oscar nominated actress turns 20 on April 12, but decided to mark it four weeks early by blowing out her candles in fancy dress.

The Carlow native is a fan of the 2011 hit comedy, as well as the female lead, Kristen Wiig.

Enjoying a day off from her hectic schedule, she held her bash over the weekend with pals.

Her guests included The Lovely Bones co-star Rose McIver -- who shared a picture on her social networking site of Saoirse dressed in a pale pink frock complete with puffy, prom-like sleeves and a silk bow around her waist.

Saoirse recently hinted what would be in store at the fete, including decorations similar to the ones from the movie's Paris-themed bridal shower.

"We're going to try and get a chocolate fountain, an Eiffel Tower, heart-shaped cookie, little toy dogs as party favours," she told Elle magazine.

"Everybody has to wear a bridesmaid dress."

And for any of the men in attendance, the dress code was a policeman outfit similar to that worn by Chris O'Dowd in the film.

Saoirse, who is currently over in the States working on upcoming film Stockholm Pennsylvania, alongside former Sex and the City star Cynthia Nixon, wanted to celebrate her birthday in America before returning home to Irish shores.

She is due to begin rehearsals for Brooklyn, opposite Domhnall Gleeson in April, before it starts shooting in Wexford in May.

Saoirse has been enjoying a very busy working period.

In between shooting various projects back-to-back, her latest film, The Grand Budapest Hotel, is on worldwide release in cinemas.

The Wes Anderson flick boasts a star-studded ensemble cast which includes heavyweight names such as Ralph Fiennes, Bill Murray and Tilda Swinton.

Saoirse described the experience as "surreal" and said the actors became like one "big, amazing family".

"It felt surreal to sit down every night for dinner with Wes at the head of this big table and people like Bill, Ralph and Tilda sitting around with you," she said.