Usher joins the lineup of performers for the Oklahoma

They join Miranda Lambert, Luke Bryan and other performers on the lineup for the May 29 event, which will air live on NBC.

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

The May 29 event, titled Healing in the Heartland: Relief Benefit Concert, will benefit 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 Miranda Lambert (who also is Shelton's wife), 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.

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.