Question: They are both singers

full_context: Document 1: Bill Champlin: William Bradford "Bill" Champlin (born May 21, 1947 in Oakland, California) is an American singer, guitarist, keyboard player, arranger, producer, and songwriter. His performance work is principally associated with the bands Chicago and the Sons of Champlin. He has won multiple Grammy Awards for songwriting.
Document 2: Vern Gosdin: Vernon "Vern" Gosdin (August 5, 1934 – April 28, 2009) was an American country music singer. Known as "The Voice" he had 19 top-10 solo hits on the country music charts from 1977 through 1990. Three of these hits went to Number One: "I Can Tell By the Way You Dance (You're Gonna Love Me Tonight)", "Set 'Em Up Joe", and "I'm Still Crazy".
Document 3: Danny Thomas: Amos Muzyad Yakhoob Kairouz (January 6, 1912 – February 6, 1991), known professionally by his stage name Danny Thomas, was an American nightclub comedian, singer, actor, and producer, whose career spanned five decades. He created and starred in one of the most successful and long running situation comedies in the history of American network television. In addition to guest roles on many of the comedy, talk and musical variety programs of his time, his legacy includes a lifelong dedication to fundraising for charity.
Document 4: Dave Van Dam: Dave Van Dam (well known as "Evil Dave Letterman" or simply "Evil Dave") is an American voice impressionist who has appeared on "The Howard Stern Show" since 1999. Van Dam impersonates the voice of American late night talk show host David Letterman, which is used to comedic effect on "The Howard Stern Show".
Document 5: Bill DeLoach: Bill DeLoach (born June 19, 1951 in Baltimore, Maryland), is a singer, keyboardist, guitarist, composer, vocal arranger, musical director, and music producer, who was a member of The Four Seasons and the musical director for entertainer Danny Gans.
Document 6: Bill Lee (musician): William James Edwards "Bill" Lee III (born July 23, 1928) is an American musician. He has played the bass for many artists including Chris Anderson, Cat Stevens, Harry Belafonte, Chad Mitchell Trio, Gordon Lightfoot, Aretha Franklin, Odetta, Simon and Garfunkel, Ian & Sylvia, Tom Rush, Burt Bacharach, Peter, Paul and Mary, Arlo Guthrie, Tom Paxton, Carolyn Hester, John Lee Hooker, Josh White, Duke Ellington, Malvina Reynolds, Eric Bibb, The Clancy Brothers and Bob Dylan. On the original release of Dylan's classic song "It's All Over Now, Baby Blue," Lee, on bass guitar, is the only musician performing other than Dylan himself. He is the father of Spike Lee.
Document 7: Frank Gorshin: Frank John Gorshin, Jr. (April 5, 1933 – May 17, 2005) was an American character actor, impressionist, and comedian. He was perhaps best known as an impressionist, with many guest appearances on "The Ed Sullivan Show" and "Tonight Starring Steve Allen". His most famous acting role was as the Riddler on the live-action television series "Batman".
Document 8: Danny Koker: "Danny Koker" (Daniel Nicholas Koker I) was an American baritone vocalist and pianist who played with the Cathedral Quartet. He was born on December 17, 1933. His parents, Mary and Stanko Koker of Yugoslavia. He was a musician, singer, composer, conductor and arranger in many quartets and bands such as: Foggy River Boys, Weatherford Quartet, The Cathedral Quartet, The Rex Humbard Family Singers and The Koker Family Singers. In 1989, he started up KFBT TV33 in Las Vegas, later becoming the WB affiliate. Danny was a Green Beret with the 10th Special Forces Group stationed in Bad Tulz, Germany, a hockey player for the U.S. Army, a baseball player and an avid automotive enthusiast. Koker also owned a television station in Las Vegas.
Document 9: Guy Marks: Guy Marks (31 October 1923 – 28 November 1987) was an American actor, comedian, singer and impressionist. A familiar face on TV sitcoms and variety shows of the 1960s and 1970s, he appeared regularly on The Ed Sullivan Show, The Merv Griffin Show, The Dean Martin Show, The Mike Douglas Show and The Joey Bishop Show. He had a natural gift for mimicry, and his impressions of celebrities such as Humphrey Bogart, Gary Cooper, Boris Karloff and many others were considered among the best. However, he also could imitate a housefly on a slippery oil cloth, neon signs, alligators, driftwood furniture, rubber bands, frozen chickens, frogs, praying mantis and—his favorite—an ostrich, all of which found their way into his act or in characters he played on TV.
Document 10: Danny Kaye: David Daniel Kaminsky (January 18, 1911 – March 3, 1987), better known by his screen name Danny Kaye, was an American actor, singer, dancer, comedian, and musician. His performances featured physical comedy, idiosyncratic pantomimes, and rapid-fire novelty songs.
Document 11: Nick Massi: Nicholas E. Macioci (September 19, 1927 – December 24, 2000), known as Nick Massi, was an American bass singer and bass guitarist for The Four Seasons.
Document 12: Bill Vernon: He was born in New York, NY. In his early teens he became enamoured with Bluegrass music and publicized and promoted that genre in many ways. He was a DJ in New York, New Jersey, and Virginia; he wrote liner notes for around a hundred recordings. In 1994 and in 1998 he received the International Bluegrass Music Association's award for best liner notes, and that organization's certificate of merit in 1988. He compiled the country music chart for Billboard magazine. He MC'd at many a bluegrass performance or festival, including Bill Monroe's Bean Blossom Festival in Indiana, and festivals of Ralph Stanley and Carlton Haney. He served as editor for Muleskinner News and wrote many articles on early bluegrass performers for that and other publications, including Bluegrass Unlimited.
Document 13: Danny Gans: Danny Davies Gans (October 25, 1956 – May 1, 2009) was an American singer, comedian and vocal impressionist.
Document 14: Bill Stevenson (musician): John William "Bill" Stevenson (born September 10, 1963) is an American musician and record producer. He is the drummer, main songwriter, and the only constant for the California punk rock group Descendents since its inception. In late December 1981 he played a few concerts with Black Flag because their drummer ROBO was detained in England after a tour there. He went on to record with Black Flag on several of their albums until 1985. After this he focused his attention on Descendents and played with them until Milo Aukerman left in 1987. After Milo had left, Bill and the others from Descendents, Karl Alvarez and Stephen Egerton, got singer Dave Smalley of Dag Nasty and formed All. All went on to have two more singers, Scott Reynolds (1989–1993) and Chad Price (1993–present). Aukerman came back to do the 1996 album "Everything Sucks", the 2004 album "Cool to Be You" and the newest, 2016's "Hypercaffium Spazzinate". All and Descendents continue to tour between Stevenson's and Aukerman's respective careers as a recording engineer and a biochemist.
Document 15: The Four Seasons (band): The Four Seasons is an American rock and pop band that became internationally successful in the 1960s and 1970s. The Vocal Group Hall of Fame has stated that the group was the most popular rock band before the Beatles. Since 1970, they have also been known at times as Frankie Valli and the Four Seasons. In 1960, the group known as the Four Lovers evolved into the Four Seasons, with Frankie Valli as the lead singer, Bob Gaudio (formerly of the Royal Teens) on keyboards and tenor vocals, Tommy DeVito on lead guitar and baritone vocals, and Nick Massi on electric bass and bass vocals.
ground_truth: American singer