Carrie Underwood & Steven Tyler: "Walk This Way" Duet!

Having kept their plans a secret until just prior to showtime, Carrie Underwood took the stage at the 46th Annual Academy of Country Music Awards for a duet with Steven Tyler.

To the delight of the packed audience on hand at the MGM Grand Garden Arena in Las Vegas, the country cutie and her "American Idol" judge singing mate delved into a rockin' rendition of Aerosmith's classic tune "Walk This Way".

Of Miss Underwood's performance plans, Jack Sussman of CBS Entertainment hinted at the special occasion by telling press prior to showtime, “Carrie Underwood will walk out and I guarantee you she will be burning down that stage…"

He added, "She’s going to do nice little duet, but wants it to be kept between her and her duet partner-and if you know her well, you know you do not want to make her upset.”