The pop princess has contributed 'Ooh La La' for the film, which is due to be released on July 31.

The song has reportedly been made with the likes of Dr Luke, Ammo and Bonnie McKee.

Speaking previously about the song, Spears said: "I have always loved the Smurfs as a kid and now my boys are the biggest Smurfs fans ever. I wanted to surprise them with a song in the movie. I know they'll think it's Smurftastic!"

The Smurfs 2 is set to star the voices of Neil Patrick Harris, Jayma Mays and also Katy Perry.

As previously reported, Spears recently confirmed long-standing rumours that she will perform a Las Vegas residency.

During the eighth inning, Diamond took over the field and sang "Sweet Caroline," a song that has been a Fenway staple for years. According to reports, Diamond showed up on his own volition.

On April 16, the day after the Boston Marathon bombings, the New York Yankees (longtime Red Sox rivals) played "Sweet Caroline" during their home game, preceeded by a moment of silence as a tribute to the victims.

Major league ballparks around the United States paid tribute to the victims and those affected by the Boston Marathon bombings by playing "Sweet Caroline" over the loud speakers at the ballpark, mainly in the middle of the eighth inning.

Other bands have paid tribute to those affected by the Boston Marathon bombings, like the Dropkick Murphys, who raised over $100k for the victims by selling their "For Boston" t-shirt.

Watch Neil Diamond perform "Sweet Caroline" at the Red Sox's Fenway Park game here:

The band have pulled forthcoming support slots with Muse in the US and Canada as well as an appearance at the Coachella Festival.

In a statement, their label said that Neil had been struggling with the problem in their last couple of concerts and that the dates have been shelved to preserve his long-term health. They said:

"Biffy Clyro have today been forced to cut short their North American tour and return to the UK immediately; Simon Neil has been struggling with a serious respiratory problem on the shows, including two nights supporting Muse at Madison Square Garden on Monday and Tuesday of this week, and was advised by doctors that he was endangering his long term health if he chose to continue performing on this run. Thus, further dates with Muse across the US and Canada, plus a second weekend performance at the Coachella Festival this coming Saturday, have now been cancelled."

The statement continued: "The band wish to express how sorry they are that they aren't able to carry out the full run of shows, and hope to confirm a new run of North American shows shortly. All UK and European dates this Summer should, however, remain unaffected."

Back in January, the 'Till The World Ends' hitmaker told her online fans that she had recorded a track "for my boys" that was going to make them "freak out when they hear it", and she has now shed more light on the project.

Writing on her social networking site earlier today (April 17), Spears confirmed that the song is called 'Ooh La La' and will be included on the soundtrack for the upcoming movie, 'The Smurfs 2':

"Remember that surprise song I recorded for my boys? It's coming soon! #OohLaLa for #TheSmurfs2 :) Stay tuned for more..."

When asked if her sons will enjoy the single, Spears confessed: "They are going to love it! #OohLaLa."

Meanwhile, 'The Smurfs 2' is set to be released in both the UK and USA on July 31 and the cast includes Neil Patrick Harris, Katy Perry and 'Glee' actress Jayma Mays.

Watch a trailer for the movie here:

GRAMMY bosses have explained that the 'With You' hitmaker's music was so popular in 2011 that it made sense to include him in the show, despite his turbulent past. Neil Portnow explained that taking the artists' personal lives into account would just create more problems:

"That's really where the judgment comes from: music professionals listening to the music of other professionals. Clearly, our voting membership rated highly Chris' musical work this past year."

"If we're going to get in trying to personally evaluate artists in terms of their personal lives, that's a slippery slope that we wouldn't want to get into."

Supporting the organisation's decision further, GRAMMY producer Ken Ehrlich told CBS show This Morning:

"I just believe people deserve a second chance. The year he had this year really brought him back into the public. He really deserved a second chance."

Watch footage of Brown's high octane set below: