Darius Rucker performs live at the 'Jimmy Kimmel Live' outdoor arena in Los Angeles. (May 22, 2013)

Darius Rucker performs live at the ‘Jimmy Kimmel Live’ outdoor arena in Los Angeles. (May 22, 2013)

*Usher and Darius Rucker have joined the lineup of performers for the Oklahoma relief concert organized and headlined by country star Blake Shelton.

The May 29 event, titled Healing in the Heartland: Relief Benefit Concert, will raise oney for the United Way of Central Oklahoma May Tornadoes Relief Fund. NBC is set to air a live broadcast of the concert at 9 p.m. ET/PT; it also will air cable networks Style, G4, Bravo, E! and CMT on either a live or delayed basis.

Usher and Rucker join a lineup that also includes Shelton’s wife Miranda Lambert Luke Bryan, Rascal Flatts, Ryan Tedder of OneRepublic, Reba McEntire and Vince Gill.

Tickets for the Heartland concert, which will take place at Chesapeake Energy Arena in Oklahoma City, went on sale Saturday morning and sold out in less than five minutes, according to NBC.

Usher appears on NBC's "The Voice" – Season 4, Episode 19 (May 22, 2013)

Usher appears on NBC’s “The Voice” – Season 4, Episode 19 (May 20, 2013)

United Way of Central Oklahoma plans to use the money raised for immediate, intermediate and long-term recovery and rebuilding efforts in Oklahoma following the tornadoes that devastated the town of Moore last week.

Usher currently is a coach alongside Shelton on NBC’s singing competition “The Voice.” The eight-time Grammy winner has sold more than 44 million albums worldwide and racked up nine No. 1 hits on the Hot 100.

Rucker, the Hootie and the Blowfish frontman-turned-country singer, released his third country album, “True Believers,” in May. Single “Wagon Wheels” hit No. 1 on Billboard’s Hot Country Chart.