Blake Shelton is a verbal guy--really verbal guy--on "The Voice" or on stage in concerts across North America. But when the affable singer got the call from Barbra Streisand to be on her "Partners" album, the usual flow of words just didn't come.

His reaction went something like this: "Who? What? How?" Shelton recalls to People of getting the phone call to sing on "I'd Want It to Be You" with Streisand.

"It's still shocking to me," he told People. "I don't know how it came down. I don't know how she knows about me, but I'm just glad. I'm just going with it!"

"Partners" debuted at No. 1 on the Billboard 200 chart on Sept. 16, making Streisand the first act to achieve No. 1 albums in each of the last six decades. "Partners" opening total was the largest sales week for a female artist in 2014, reports Billboard

Her first No. 1 album, "People," arrived 50 years ago in October 1964.

On "Partners," Streisand performs duets of classic tracks with some of the biggest male artists, reports cnn.com. There's "New York State of Mind" with Billy Joel and "The Way We Were" with Lionel Richie. She even sings a virtual duet with Elvis Presley on "Love Me Tender."

Shelton sang is own kind of virtual duet with Streisand-since he didn't actually get to record the song's lines with the legendary songstress in person.

"Ironically enough, she had already done her vocal part and I was really disappointed because when I went to the studio, she wasn't there," the country star explains, reports Coti Howell of Taste of Country. "I was like, 'Oh, man, we ... that's ... I still get to be on her record with her and that's bada--.' "

Shelton says the moment was definitely "nerve-wracking," but said Streisand was "humble" and "appreciative" of what he did. She showed her appreciation with a pretty fancy gift, one Shelton says is the best thing on his mantle, adds Howell.

"She sent me a piece of crystal that was like, 'Thank you, Love Barbra.' I pushed all my awards away and put that in the middle," he insists, adds Taste of Country. "It was so cool, like, 'See, she knows me. I knew it.'"

You can see Shelton and Streisand to their duet thing on "I'd Want It to Be You" here:

https://www.youtube.com/watch?v=vstb1Y124NE

https://www.people.com/article/blake-shelton-barbra-streisand-partners-duet

https://tasteofcountry.com/blake-shelton-barbra-streisand-gift/?trackback=tsmclip

https://www.cnn.com/2014/09/25/showbiz/music/barbra-streisand-billboard-record/

https://www.billboard.com/articles/columns/chart-beat/6259282/barbra-streisand-no-1-partners