AceShowbiz - Justin Timberlake surprised fans in Nashville, Tennessee on Wednesday, May 9, by reuniting onstage with his country music collaborator Chris Stapleton. The pop superstar is currently on the road for his "Man of the Woods" Tour, and when the show touched down in Stapleton's home city, the pair decided to serve up a treat for attendees.

According to The Tennessean, Stapleton's arrival wasn't even officially announced as he walked out to perform their tune "Say Something" with Justin, drawing cheers from audience members as they realized who the special guest was. Chris also delivered a rendition of "Tennessee Whiskey", the George Jones track he covered on his debut album, "Traveller".

The two musicians previously teamed up onstage for a special duet at the 2015 Country Music Association (CMA) Awards, and when Justin reached out to Stapleton to hit the studio for his recent "Man of the Woods" album, the country artist thought he would just be working as a songwriter.

Confessing he didn't expect to be adding vocals to "Say Something", he told Billboard in January, "I really just went out to Los Angeles to write songs with him. That was one of those things where there wasn't necessarily a plan. He was like, 'Alright, you hop in there and take a verse.' I'm like, 'You want me to do what...?' " However, the end result "came out great": "I had a blast with him," Chris shared. "He's a great creative force and one of those guys that if you get a chance to work with him, you should."

Stapleton also co-wrote "Morning Light", Justin's duet with Alicia Keys, and "The Hard Stuff", while he can also be heard playing guitar on "Filthy".