Steven Tyler, Rihanna Perform at Academy of Country Music Awards; Miranda Lambert Wins Big

Steven Tyler provided one of the big surprises of the evening at the 46th annual Academy of Country Music Awards. The Aerosmith star and American Idol judge joined past Idol winner Carrie Underwood for a rousing rendition of her hit "Undo It" before the two segued into a flirtatious performance of his band's '80s classic "Walk This Way."

Music worlds collided again Sunday when Rihanna performed "California King Bed" with Sugarland's Jennifer Nettles. James Taylor also joined Zac Brown Band onstage for a medley of "Colder Weather" and "Sweet Baby James."

See all the Academy of Country Music Awards red carpet arrivals

Miranda Lambert took home a leading four awards at the ceremony, hosted by Reba McEntire and Lambert's fiancé, Blake Shelton. To open the show, McEntire and Shelton poked fun at country's royal couple by showing Shelton performing in a candle-lit hotel room to a blond wig-wearing McEntire.

Other big winners of the night included Lady Antebellum with two awards and Taylor Swift, who won Entertainer of the Year for the first time.

Check out the full list of winners:

Entertainer of the Year: Taylor Swift.

Top Male Vocalist of the Year: Brad Paisley

Top Female Vocalist of the Year: Miranda Lambert

Top Vocal Group of the Year: Lady Antebellum

Top Vocal Duo of the Year: Sugarland

Top New Artist of the Year: The Band Perry

Album of the Year: Need You Now, Lady Antebellum

Single Record of the Year: "The House That Built Me," Miranda Lambert

Song of the Year: "The House That Built Me," Miranda Lambert

Video of the Year: "The House That Built Me," Miranda Lambert

Vocal Event of the Year: "As She's Walking Away," Zac Brown Band Featuring Alan Jackson