In 1963, Bill Medley and Bobby Hatfield were performing a series of shows at a military base in Orange County, Calif. According to Medley, Marines would greet the singers afterward and frequently say “That was righteous, brothers!” The duo adopted the compliment as their official name and The Righteous Brothers were born.

Fifty-seven years later, the legacy continues at The Righteous Brothers: Bill Medley and Bucky Heard. It’s an evening of entertainment that spans the generations and touches the heart. Backed by a sizzling live band and a trio of female vocalists (including Medley’s daughter McKenna), the production at Harrah’s delivers a timeless collection of unforgettable hits.

Medley has said that the servicemen who inspired their name were of African-American descent and were impressed that a pair of white guys could sing R&B with such coolness. DJs agreed and categorized their music as “blue-eyed soul,” a description that remains today.

At the age of 19, Medley penned “Little Latin Lupe Lu,” a catchy record that Hatfield hand-delivered in stacks to local record stores. Bolstered by live performances in area clubs, the “stupid little song” (as Medley has called it) sold every copy. Radio stations caught wind of its success and there was no looking back.

In 1964, pioneering music producer Phil Spector signed the pair as his first “white” group. Using his “Wall of Sound” studio technique, Spector expanded The Righteous Brothers’ sonic impact and catapulted them to the top of the charts. Soon they were opening for The Beatles and The Rolling Stones.

“You’ve Lost That Lovin’ Feelin’” became the group’s first smash. It reached No. 1 in 1965, the same year that Frank Sinatra brought them to Vegas to play at The Sands. Belting out live performances of “Unchained Melody” and “Just Once In My Life,” Righteous Brothers joined Elvis Presley and The Rat Pack as Sin City favorites.

The duo split three years later and Medley pursued a successful solo career. Singer Jimmy Walker of The Knickerbockers stepped into Medley’s spot but couldn’t replicate the original group’s success. The guys reunited in ’74 and were quickly back on the charts with “Rock and Roll Heaven.”

The ’80s and ’90s were especially successful for The Righteous Brothers. They found a new audience thanks to Top Gun (“You’ve Lost That Lovin’ Feelin’”), then Medley’s “(I’ve Had) The Time of My Life” with Jennifer Warnes (from Dirty Dancing) won a Grammy for Best Pop Duo. “Unchained Melody” returned to the charts in 1990 after being featured in the film Ghost. Both the original recording and their brand-new version landed in the top 20 at the same time, a historic first for any artist.

Sadly, Hatfield died in 2003, shortly after The Righteous Brothers were inducted into the Rock and Roll Hall of Fame. Medley longed to keep the group’s sound alive, but, at the time, found Hatfield irreplaceable. Yet, years later, he remembered his old friend Bucky Heard (The Horn Dawgs), whose vocal range resembles Hatfield’s, and asked him to join the group. Heard accepted to come on board, and the new Righteous Brothers have been bringing blue-eyed soul back to Las Vegas ever since.

Harrah’s, 6 p.m. Tues.-Thurs., $49-$125 plus tax and fee. 702.777.2782