Love how when Steven walks out everyone in the crowd stands up, they know they are in the presence of a legend. The 2011 Academy of Country Music (ACM) Awards will forever be remembered for one of the most electrifying performances in the show’s history.

That night, country superstar Carrie Underwood and rock legend Steven Tyler joined forces for a high-energy, genre-blending duet that sent the crowd into a frenzy.

Their mashup of Underwood’s hit “Undo It” and Aerosmith’s classic “Walk This Way” created a moment that not only stole the show but also cemented itself as one of the greatest collaborations in ACM history.

The performance kicked off with Underwood commanding the stage, belting out her 2010 hit “Undo It” with her signature powerhouse vocals. Dressed in a stunning white mini dress, she captivated the audience with her electrifying presence.

But just when fans thought they were getting a classic Underwood performance, the unexpected happened—Steven Tyler stormed onto the stage, immediately raising the energy level to new heights.

As the rock icon joined in on “Undo It”, the excitement in the venue was undeniable. The chemistry between the two was instant, and their vocal harmonies blended effortlessly despite coming from two completely different musical worlds.

Then, without missing a beat, the duo launched into Aerosmith’s legendary anthem “Walk This Way”, with Tyler’s signature raspy vocals and Underwood proving she could go toe-to-toe with one of rock’s greatest frontmen.

From the moment Tyler grabbed the mic, the crowd at the MGM Grand Garden Arena in Las Vegas erupted into cheers. Even country music veterans in the audience were on their feet, taken aback by the sheer energy and intensity of the performance.

Underwood, typically seen as a polished country queen, showed a new, edgier side as she danced across the stage with Tyler, feeding off his rockstar charisma.

Meanwhile, Tyler—famous for his wild stage antics—brought his signature moves, effortlessly commanding the audience and proving why he’s one of rock music’s greatest performers.

The duo’s energy was contagious, and their onstage chemistry was so strong that it felt like they had been performing together for years.

The performance was a perfect storm of rock and country colliding in the best way possible.

It wasn’t just two artists performing side by side—it was a true musical fusion, with both Underwood and Tyler stepping into each other’s worlds and creating something that neither could have achieved alone.

The impact of this performance was immediate. Fans took to social media, calling it “legendary,” “unexpected,” and “one of the best ACM moments ever.”

Even music critics, who often scrutinize country-pop crossovers, praised the duet for its boldness and seamless execution.

But the collaboration didn’t just wow the audience—it set a new standard for cross-genre performances at country music award shows.

The ACMs had seen rock and pop artists perform before, but never in such a seamless and natural way. It wasn’t just about adding a rockstar to the stage for the sake of a ratings boost—Underwood and Tyler genuinely complemented each other, making the performance feel organic rather than forced.

Following the ACMs, fans clamored for another collaboration, and their wishes were soon granted. Later that year, Underwood made a surprise appearance during Aerosmith’s performance on “American Idol,” performing “Walk This Way” once again with Tyler.

Their onstage chemistry was undeniable, proving that their ACM performance was far from a one-time fluke.