Luke Bryan pulled off a shocking win on Sunday night when he beat out heavyweights Blake Shelton, Jason Aldean, Miranda Lambert and Taylor Swift to win the Academy of Country Music Award's biggest prize of the evening: entertainer of the year. The winner is chosen by fan votes.

The musician, who co-hosted the show with Shelton, was stunned after his name was announced, and appeared to cry as he slowly walked out from backstage to accept the award from Shania Twain, who was making her first appearance at the ACMs in 10 years. Even with his trophy in hand, Bryan stood in silent shock at the microphone for a long while.

"This is ... I don't know what to say, you guys," he finally started. "Thank you guys so much, fans, for doing this to me, thank you so much for making my life what it is. What I always wanted to be was just a country singer that got to ride on a tour bus and show up on a new stage and play music every night. … I just started headlining! … Every time I step on stage, it is a blessing to me to play for fans. ... This is the defining moment of my life!"

Bryan, 36, been on the scene since his debut album was released in 2007, but wasn't a headlining act until his single "Country Girl (Shake It for Me)" exploded after he started delivering booty-shaking performances of the catchy tune at awards shows in 2011.

Slideshow: 2013 Academy of Country Music Awards

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The other big winner of the night was Shelton's wife, Miranda Lambert. She took home three of the four trophies she was nominated for: song and single record of the year for "Over You," and female vocalist for the fourth year in a row. Lambert shared the song of the year victory with her husband, who co-wrote the tune.

"Last time this happened, you didn't get a chance to talk, and you're not going to get a chance either this time," he joked as he and his wife accepted their trophies. "I'll tell you all something: I’ve learned so much from this human being standing next to me … she blows me away, but as far as standing here right now, I used to think I was a decent songwriter until I started hanging out with her."

Notable moments from the show included Garth Brooks and George Strait's performance together; Reba McIntire's announcement that the ACM was "renaming its most prestigious honor to the ACM Dick Clark Artist of the Decade Award"; and Stevie Wonder closing the show with "Signed, Sealed, Delivered."

The complete list of winners:

• Entertainer of the year: Luke Bryan
• Male vocalist: Jason Aldean
• Female vocalist: Miranda Lambert
• Vocal duo: Thompson Square
• Vocal group: Little Big Town
• New artist: Florida Georgia Line
• Album: Eric Church, "Chief"
• Single record of the year: Miranda Lambert, "Over You"
• Song: Miranda Lambert, "Over You"
• Video: Little Big Town, "Tornado"
• Vocal event: "The  Only Way I Know," Jason Aldean with Luke Bryan and Eric Church
• New male vocalist: Brantley Gilbert
• New female vocalist: Jana Kramer
• New vocal duo or group: Florida Georgia Line

The 48th Annual ACM Awards was held at the MGM Grand in Las Vegas.

The Associated Press contributed to this report.

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LAS VEGAS -- It was a night for married couples at the Academy of Country Music Awards on Sunday as husband and wife Blake Shelton and Miranda Lambert won several honors and a couple of country music fans married during the show.

Slideshow: Academy of Country Music Awards

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The show spanned the years of country music with 22-year-old sensation Taylor Swift winning the top honor, entertainer of the year, and audience members paying tribute to bluegrass legend Earl Scruggs, who died last week in Nashville at age 88.

"I am so amazed that the fans keep doing such incredibly nice things for me. I just want to hug them all the time and thank them for everything -- it really blows my mind," Swift told reporters backstage about the award, which fans vote for.

But Shelton and Lambert, who married last year, were the big winners, taking home three trophies between them including best male vocalist for him and two trophies for her, female vocalist and album of the year for "Four the Record."

Shelton, who co-hosted the program, seemed genuinely surprised, saying he'd been waiting in the wings and hadn't even been thinking of the award when his name was called. "I didn't see that coming, at all," he said. "It's amazing."

Accepting her trophy for "Four the Record," Lambert called her albums her "babies."

"That's why I wake up in the morning," she said.

Jason Aldean and Kelly Clarkson also walked off with two awards, single record of the year and vocal event of the year for their duet "Don't You Wanna Stay."

Lady Antebellum, fresh off their smash hit "Need You Now," was named best vocal group -- the fourth time it had won the award in recent years. The Eli Young Band took song of the year honors with "Crazy Girl."

"I have dreamed about this moment my whole life," Mike Eli said. He told aspiring artists: "Follow your dreams, believe in yourself and do it."

Former "American Idol" contestant Scotty McCreery, 19, who recorded the hit single "Water Tower Town," was named best new artist. Among honors announced backstage, video of the year went to Toby Keith for his popular party song, "Red Solo Cup."

Keith had one of the night's memorable performances singing the song in the packed MGM Grand Arena while audience members swayed to the music and held red cups in the air.

Hosted by Shelton and Reba McEntire, the Academy of Country Music Awards is among the biggest events in country music.

Toward the end of the show, a pair of country music fans got married on stage, in what was billed as the first live wedding on a televised awards show.

Christina Davidson, 31, and Frank Tucci, 33, exchanged vows while Martina McBride and Train's Pat Monahan sang a duet of the hit song, "Marry Me."

Davidson lost her husband Paul in a drowning accident in 2009, and later founded a support group for young widows and widowers in New Jersey, where she met Tucci, whose wife lost her life to cancer.

The show featured numerous performances. Carrie Underwood started off the program with her rocking song "Good Girl," and Kenny Chesney and Tim McGraw belted out "Feel Like a Rock Star."

Not to be outdone, Keith Urban put on an electric guitar show with "For You," and in keeping with tradition, the Academy of Country Music invited stars from other musical genres to appear, including U2 singer Bono and the members of KISS.

But the old days of country were not forgotten, either. In perhaps the most poignant moment of the night, the star-filled audience gave a standing ovation for banjo picker Earl Scruggs, whose funeral was held in Nashville on Sunday.

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Nothing is more gorgeous than a southern belle! At the 47th Annual Academy of Country Music Awards in Las Vegas Sunday, three 20-something starlets were throwing down for the most wow-worthy red carpet ensemble.

AP, Getty, Reuters

Carrie Underwood, left, Miranda Lambert, center, and Taylor Swift on Sunday night in Las Vegas.

Carrie Underwood, 29, showed some leg in her strapless Abed Mahfouz couture chiffon gown with a hip-high slit teamed with silver peep-toe heels. She wore her hair in her signature over-the-shoulder curls and loaded up on mascara and nude lip gloss.

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Miranda Lambert, 28, sparkled in Randi Rahm's tone-on-tone liquid gold sequin and stone gown, which she paired with matching peep-toe heels. Her hair was done in side-parted waves and her makeup looked radiant and flawless.

PHOTOS: Miranda and Blake's love story

Taylor Swift, 22, ditched her sparkly, sequin-adorned frocks like in years past and went with a sleek white floor-length dress with cut outs at the waist and gold detail. Her wiry curls were blown out into soft waves and she loaded up on black eyeliner and false lash strips.

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