The country stars teamed up to celebrate Nelson's 70th birthday back in 2003.

What do you get when you combine two music legends and one iconic tune? Chills.

Thanks to Whiskey Riff for reminding us of the time Willie Nelson and Shania Twain took the stage together to create one of the most beautiful duets in country music history.

Willie Nelson and Shania Twain
Credit: KMazur/Getty Images

Back in 2003, Twain was featured on Willie Nelson and Friends: Live and Kickin', a live album recorded in honor of Nelson's 70th birthday. The album also includes performances by Sheryl Crow, Kenny Chesney, Eric Clapton, and Toby Keith.

For her part in the star-studded tribute, Twain joined Nelson on a moving cover of "Blue Eyes Crying In The Rain," which appeared on the latter's 1975 album Red Headed Stranger.

The sorrowful tune was written in the 1940s by Fred Rose and previously recorded by Roy Acuff and Hank Williams. In their modern reimagining, Twain pours her heart and soul into the mournful lyrics while Wilson provides harmony and guitar accompaniment.

"Blue Eyes Cryin' In The Rain" was Nelson's first No. 1 song on the Billboard charts and ultimately saved his music career.

Oh, to have been able to witness him and Twain perform it together live, nearly 30 years later.