Merle Ronald Haggard (April 6, 1937 – April 6, 2016) was an American country singer, songwriter, guitarist, and fiddler. Haggard was born in Oildale, California, during the Great Depression. His childhood was troubled after the death of his father, and he was incarcerated several times in his youth. After being released from San Quentin State Prison in 1960, he managed to turn his life around and launch a successful country music career, gaining popularity with his songs about the working class that occasionally contained themes contrary to the prevailing anti-Vietnam War sentiment of much popular music of the time. Between the 1960s and the 1980s, he had 38 number-one hits on the US country charts, several of which also made the Billboard all-genre singles chart. Haggard continued to release successful albums into the 2000s.

Elvis Costello is an English pop/rock musician, singer, songwriter, composer, record producer, author, television presenter, and occasional actor. He has won multiple awards in his career, including a Grammy Award and has twice been nominated for the Brit Award for Best British Male Artist. In 2003, Costello and the Attractions were inducted into the Rock and Roll Hall of Fame. In 2004, Rolling Stone ranked Costello number 80 on its list of the 100 Greatest Artists of All Time. Costello has co-written several original songs for motion pictures, including "God Give Me Strength" from Grace of My Heart (1996, with Burt Bacharach) and "The Scarlet Tide" from Cold Mountain (2003, with T-Bone Burnett). For the latter, Elvis was nominated (along with Burnett) for the Academy Award for Best Original Song and the Grammy Award for Best Song Written for Visual Media.

Wanda Lavonne Jackson is an American singer, songwriter, pianist and guitarist who had success in the mid-1950s and 1960s as one of the first popular female rockabilly singers and a pioneering rock-and-roll artist. She is known to many as the “Queen of Rockabilly” or the “First Lady of Rockabilly”.

Jackson mixed country music with fast-moving rockabilly, often recording them on opposite sides of a record. As rockabilly declined in popularity in the mid-1960s, she moved to a successful career in mainstream country music with a string of hits between 1966 and 1973, including “Tears Will Be the Chaser for Your Wine”, “A Woman Lives for Love” and “Fancy Satin Pillows”.

Leon Russell was an American musician and songwriter who was involved with numerous bestselling pop music records during his 60-year career. His genres included pop, country, rock, folk, gospel, bluegrass, rhythm and blues, folk rock, blues rock, surf, standards, and Tulsa Sound.

His collaborations rank as some of the most successful in music history, and as a touring musician he performed with hundreds of notable artists. He recorded 33 albums and at least 430 songs. He wrote "Delta Lady", recorded by Joe Cocker, and organized and performed with Cocker's Mad Dogs and Englishmen tour in 1970. His "A Song for You", added to the Grammy Hall of Fame in 2018, has been recorded by more than 200 artists, and his "This Masquerade" by more than 75.

Roy Clark was an American singer and musician. He is best known for having hosted Hee Haw, a nationally televised country variety show, from 1969 to 1997. Clark was an important and influential figure in country music, both as a performer and in helping to popularize the genre.

During the 1970s, Clark frequently guest-hosted for Johnny Carson on The Tonight Show and enjoyed a 30-million viewership for Hee Haw. Clark was highly regarded and renowned as a guitarist, banjo player, and fiddler. He was skilled in the traditions of many genres, including classical guitar, country music, Latin music, bluegrass, and pop. He had hit songs as a pop vocalist (e.g., "Yesterday, When I Was Young" and "Thank God and Greyhound"), and his instrumental skill had an enormous effect on generations of bluegrass and country musicians. He became a member of the Grand Ole Opry in 1987, and, in 2009, was inducted into the Country Music Hall of Fame.