­LOS ANGELES(RS): Chart-topping English indie folk rock band Mumford and Sons postponed three sell-out shows on their US tour Tuesday while bassist Ted Dwane undergoes surgery for a blood clot.

Writing on its website, the group -- winners of this year's Grammy for best album -- said scans had revealed a blood clot on the surface of Dwane's brain that requires immediate treatment.

"Ted is receiving excellent care and we are being assured that he will recover quickly from surgery," it said without disclosing where the operation will take place.

Dwane, who plays upright bass, turns 29 on August 15.

In the interim, Mumford and Sons is postponing headlining concerts this week in Dallas and Woodlands, Texas and in New Orleans, Louisiana. Tickets will be honored at rescheduled dates.

"We have no plans to cancel or postpone any other appearances along this current tour," said the band, which is lined up to play the Lollapalooza festival in Chicago on August 3.

Mumford and Sons have been at the forefront of a folk and bluegrass revival that also includes The Lumineers from Colorado. Its latest album "Babel" entered the British and US charts at number one upon its release in September.

She is rarely seen in public without looking immaculate in a designer dress and heels.

But Mariah Carey has proved she’s not scared to bare all as she appears stripped back in a first look at her character Hattie Pearl in Lee Daniels’ The Butler.

The official image shows the superstar without a scrap of make-up and in a frumpy ensemble as she takes on the role of a field slave.

Looking a far cry from her usual self the 43-year-old shows off her natural beauty while her typically very styled hair is pushed off her face and tied up in a rag.

The We Belong Together songstress is looking wistfully at the camera while picking cotton in a film surrounded by fellow cotton pickers.

Mariah is not the only big name to star in the movie – it also features heavyweights Forest Whitaker, John Cusack and Oprah Winfrey.

The Butler is filmed in New Orleans and tells the true story of Eugene Allen, who is played by Forest Whitaker.

Eugene served under eight president presidents during his 1952-1986 stint as the White House butler.

The film will document the changes in American society over the period, which includes the civil rights movement and Vietnam, and how the various things affect Eugene and his family. 

The actors on board to play the presidents are particularly impressive including Robin Williams as Dwight Eisenhower, John Cusack as Richard Nixon, Alan Rickman as Ronald Reagan, James Marsden as John F. Kennedy and Liev Schreiber as Lyndon B. Johnson.

It is unclear at this stage how big a role Mariah will have in the film playing Hattie.

It will of course not be the mother-of-twos first foray into acting - over the years she has starred in rather a mixed bag of films.

Her biggest flop was without a doubt Glitter in 2001, a romantic musical drama film, in which Mariah played the protagonist Billie Frank.

She received the 2001 Golden Raspberry Award for Worst Actress for her role in the film.

However in 2009 she fully redeemed herself with her portrayal of Mrs Weiss in the Oscar nominated film Precious.

Her participation in the harrowing tale won her numerous awards and nominations including the Palm Springs International Film Festival Breakthrough Performance Award.

Meanwhile her co-star Oprah, who plays Gloria Gaines in the film, has announced her pledge to help build the Smithsonian institution's forthcoming National Museum of African American History and Culture in Washington D.C.

The 59-year-old star will have the facility's 350-seat theatre named after her as a special thanks.