Lady Gaga and Justin Bieber were the undisputed stars of the show at the 2011 MTV Europe Music Awards, held Sunday night (Nov. 6) at Belfast Odyssey Arena, Northern Ireland.

Lady Gaga won four awards, including best female and biggest fans, a newly created category that celebrates artists with the most committed fan base. Her hit single "Born This Way" won best video and best song.

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"I knew that this song was very special when I first wrote it," she told the audience upon receiving the best song prize. "This is the single most important song that I've ever written, the single most important album, and until now the single most important moment."

She also caused a small ripple of controversy in the otherwise slick, family friendly show, which is broadcast live. Referring to an earlier joke by guest host David Hasselhoff, who presented her with the best female award and joked that he had drilled a hole in his dressing room wall so women could watch him undress, Gaga told the actor that she had looked through the hole and "you do have a big penis."

A subsequent live performance of "Marry The Night," which saw the artist singing atop a giant half-moon stage set wearing a blue circular face mask, ended with Gaga mooning the 8,000 strong crowd.

"'I'm really smiling right now, but I know you can't tell. I've had a lot of Botox," Gaga said accepting the best female award.

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Justin Bieber, who performed a two-song medley of "Under The Mistletoe" and "Never Say Never" won best male and best pop. Accepting the best male award, Bieber said that he had voted for fellow nominee Kanye West before thanking his fans, family and MTV.

Coldplay opened the show with a rousing run through "Every Teardrop Is A Waterfall," taken from their recent U.K. and U.S. No. 1 album "Mylo Xyloto." Other live performances on the evening included Bruno Mars singing "Marry You," Jessie J leading the crowd through "Price Tag," and host Selena Gomez with a rendition of "Hit The Lights."

David Guetta teamed up with Taio Cruz, Ludacris and Jessie J for a dazzling dance mix, while LMFAO began their colorful live set by traveling through the crowd in a revolving zebra shaped vehicle.

Footage of Red Hot Chili Peppers playing "The Adventures of Rain Dance Maggie" was broadcast live from Ulster Hall, Belfast, where the band was performing. U.K. rock act and local heroes Snow Patrol also performed live outside broadcast to over 15,000 fans from a specially built stage in front of Belfast City Hall, as part of the show.

Big winners on the night included Bruno Mars, who took best new artist. "I've never been in this position," said the clearly delighted singer. "I don't know what do. Kids follow your dreams."

The award for best live went to Katy Perry. Accepting the gong, the artist -- who is currently touring the U.K. -- thanked fans for voting for her.  "It's really easy to download, buy and steal a song, but it takes commitment to go to a live show," she continued, adding, "I'm so tired but it's worth it."

Eminem accepted the title of best hip hop artist in a pre-recorded video. The inaugural worldwide act award went to Korean boy band BIGBANG, representing Asia Pacific.

Linkin Park won best rock but was not present at the event, which is broadcast live to a potential audience of over 640 million homes and 1.2 billion people. The 2010 MTV EMAs, which was held in Madrid, were watched by 22 million people with an additional 4.5 million viewing online, according to MTV. A total of over 180 million public votes were cast for this year's edition, according to MTV. The evening also featured a moving film tribute to Amy Winehouse, introduced by Jessie J.

"I never got to thank Amy for breaking boundaries as I truly believe without her I wouldn't be standing here today," she said. "She set a new standard for British female artists."

As previously announced, Queen was honored with the global icon award, presented by Katy Perry, who told the crowd that first discovering the band at the age of 13 was a life changing experience for her.

"From that moment on I knew who I was," she said. "I would not be standing here today without the power, the passion and the drama of Queen."

Accepting the award alongside band mate Roger Taylor, Brian May said: "We were at the birth of MTV. How wonderful for us to be here forty years later."

May and Taylor closed the show with "American Idol" star Adam Lambert joining the duo for a suitably epic run through Queen hits "The Show Must Go On," We Will Rock You" and "We Are The Champions." Watch below.

NEXT: Full List of Winners