The ‘Don’t Start Now’ singer, 24, filled in as guest host on Jimmy Kimmel Live! Monday, August 10.
The former model spoke with Stefani to discuss their musical inspirations and life during the quarantine. The mishap happened when Lipa began to talk about the 'No Doubt' singer's long term boyfriend, country singer Shelton.
English singer Lipa mistakenly called Shelton, 44, Stefani's “husband”.
"So I heard that you've been spending quarantine with your husband Blake Shelton at the ranch in Oklahoma," Lipa, 24, said as Stefani smiled. "Who else was with you? How was that?"
After a slight hesitation, the former Voice judge responded, "Um, well ... he's not my husband, but that sounded cool when you said it."
Realizing that she had misspoken, the ‘New Rules’ singer quietly responded "Oh" and the two began to crack up laughing.
The two superstars quickly got back on track, with Stefani revealing that she and Shelton have been quarantining at Shelton’s ranch in Oklahoma with her three sons - Kingston, 14, Zuma, 11, and Apollo, 6 - along with other members of her family.
"We were actually on his tour right when we got shut down," Stefani shared. "My brother was out with us. So his whole family came out. So it was me, my three boys, Blake, and then my brother, his wife, their two little babies, kids, and then her sister and then a friend."
"I think there were like 15 people," she added. "It was really actually a lot of fun at first. Because it's like, all of the sudden, work is over and you just get to indulge and just being on this ranch ... every day was like a new thing."
While talking to PEOPLE, Shelton recently opened up about how he and Stefani were taking advantage of spending quality time together during the quarantine.
"The simple pleasure of being together in one place for an extended period of time has been a real gift," he said. "We cook, we clean, we ride four-wheelers and we just enjoy being with each other and with family."
The superstar couple recently released their fourth duet together, 'Happy Anywhere.'
The music video, which was shot in Oklahoma, gives viewers insight into the couple’s everyday life together during the pandemic.
“There was a camera shooting the things we do every day,” Shelton said. “We make biscuits, fish, sing together, spend time with family… just a day in life!”
The ‘God’s Country’ singer added that having Stefani on the new song was a “no-brainer.”