Speaking of McEntire's big night, Clarkson marveled at the magnitude of the honor.
"It's just such a prestigious award to get in the first place, so that's amazing. Especially [since] I thought maybe she already had this. Like, I didn't know," Clarkson admitted to ET of her former mother-in-law and close friend. "So whenever they called and asked if I would sing with her I was like, 'Of course!'"
"[I'm] insanely busy but I'd do anything for her because she's really been not only such a cool idol musically, but a really great friend and a great family member," Clarkson continued. "She's just a really impeccable human."
Check out Clarkson's performance when the 41st Annual Kennedy Center Honors ceremony airs Dec. 26 on CBS.
Sonny and Cher over the years
Sonny and Cher over the years
Musical duo Sonny Bono And Cher dancing at the party following the premiere of the movie 'Dr Dolittle', at the Hollywood Paramount Theatre, CA, December 21st 1967. (Photo by Frank Edwards/Archive Photos/Getty Images)
12th December 1967: A headshot of married American pop singers Cher (left) and Sonny Bono (1935 - 1998) of the pop duo Sonny and Cher at an S.D.G. party for actor James Coburn. Cher has bangs and a bouffant ponytail on top of her head; she wears dramatic eye makeup and false eye lashes. Sonny wears a bohemian peasant blouse with floral embroidery. (Photo by Frank Edwards/Fotos International/Getty Images)
LOS ANGELES - JUNE 12 Singer Sonny Bono and singer Cher on June 12, 1977 arrive at the Los Angeles International Airport in Los Angeles, California. (Photo by Ron Galella/WireImage)
KRAFT MUSIC HALL -- 'The Phyllis Diller Happening' Episode 1006 -- Pictured: (l-r) Sonny & Cher: Cher, Sonny Bono -- (Photo by: NBC/NBCU Photo Bank via Getty Images)
Close-up of Sonny Bono and Cher head-to-head, looking upward. (Photo by Arnaud de Rosnay/Condé Nast via Getty Images)
LOS ANGELES - MAY 19: Sonny and Cher on THE SMOTHERS BROTHERS COMEDY HOUR. Image dated May 19, 1967. (Photo by CBS via Getty Images)
British model and actress Twiggy (right) with American singing duo Sonny Bono (1934 - 1998) and Cher at an outdoor party given to welcome Twiggy to Los Angeles, Beverly Hills, April 30, 1967. Sonny and Cher are wearing matching saffron outfits of a thick patterned material. (Photo by Hulton Archive/Getty Images)
Sonny & Cher 1965 (Photo by Chris Walter/WireImage)
(NO AGENCIES IN UK, FRANCE, GERMANY, HOLLAND, SWEDEN, FINLAND, JAPAN.) Sonny & Cher 1965 during Music File Photos - The 1960s - by Chris Walter at the Music File Photos 1960's in London, United Kingdom. (Photo by Chris Walter/WireImage)
GERMANY - CIRCA 1960: Photo of SONNY & CHER (Photo by K & K Ulf Kruger OHG/Redferns)
1970: Sonny (1935-1998) and Cher Bono pose for a promotional photo for 'The Sonny and Cher Show' in 1970. (Photo by Martin Mills/Getty Images)
(Original Caption) Hollywood: Sony Bono and Cher Allman, failled to attain success in separate show business careers following their estrangement and divorce, said a press conference they are getting back together next year in a new television variety show. They emphasized that the reunion was soley for business purposes. Remarriage was not in their future, they said.
CIRCA 1978: Entertainers Sonny Bono & Cher attend an event in circa 1978. (Photo by Michael Ochs Archives/Getty Images)
Portrait of Cher and Sonny Bono photographed in 1965.; (Photo by King Collection/Photoshot/Getty Images)
(Original Caption) Sonny and Cher are together again- on television and briefly July 14. After Sonny Bono finished performing on the Tonight Show, Cher came on as a surprise guest. It was assumed that Sonny knew that Cher, his former wife, was going to come on, but actor George Segal, guest host, didn't. Sonny and Cher were divorced June 27th. Cher married Greg Allman June 30th and there were reports that she filed for divorce nine days later.
Portrait of singing duo Sonny Bono and Cher, wearing formal dress on an outdoor patio, circa 1975. (Photo by Archive Photos/Moviepix/Getty Images)
Cher and Sonny during Sonny Bono and Cher Arrive at JFK - July 20, 1977 at JKF Airport in New York City, New York, United States. (Photo by Ron Galella/WireImage)