The 47-year-old singer discussed her professional dynamic with the 40-year-old country star on Wednesday's episode of the Today show, saying her work life with Shelton is "easy and comfortable," not "awkward."
"[I love] the chemistry between the coaches!" Stefani said. "Alicia Keys is just so magical. Adam [Levine] and I, we've known each other now for a while. And, of course, Blake, who I think is the greatest guy ever. It's just so fun. It's so easy and comfortable."
"[Working with Blake made me] nervous at first. I was like, 'Wait is this going to be awkward? How am I going to act?' It's just natural," she shared. "We actually do help each other, and I've learned a lot about country music -- just in the last year -- through him."
Stefani and Shelton met on The Voice in 2014, and started dating the next year following their splits from their respective spouses, Gavin Rossdale and Miranda Lambert. The couple were apart Tuesday for Valentine's Day, but still managed to connect.
"He forgot [to call]," the singer joked before sharing, "I got some beautiful flowers and lots of texts. It was fun."
Stefani and Shelton will both serve as coaches on The Voice Season 12, which premieres Feb. 27 on NBC. The singer previously served as a coach in Seasons 7 and 9, while Shelton has been with the show since Season 1.
"It's so good. It's just a different perspective being back and listening to all the music, and I have such an amazing team," Stefani told Access Hollywood. "I love [Adam Levine], and I love Alicia Keys, and obviously, I love Blakey. It's just so fun. I love it here."