The pair fell in love on the set of The Voice in 2015 and got engaged in Oklahoma earlier this month
Gwen and Blake
Blake Shelton, Gwen Stefani
| Credit: Steve Granitz/WireImage

Blake Shelton's proposal this month to Gwen Stefani was a total surprise to the No Doubt singer — but she couldn't be happier to say "yes please!"

Two days after the couple announced their engagement, a source tells PEOPLE that Stefani, 51, is "ecstatic" to be the country star's fiancée.

"Gwen is ecstatic. The proposal was a surprise," the insider says. "Gwen and Blake kept the proposal quiet for a few days, but were very excited to share."

The duo, who have been dating since falling in love on the set of The Voice in 2015, revealed the happy news with matching Instagram posts on Tuesday.

"@blakeshelton yes please! 💍🙏🏻 gx" Stefani wrote in the caption for a photo from the engagement, holding up her new ring and giving Shelton a smooch on the lips.

Gwen and Blake
Gwen Stefani and Blake Shelton
| Credit: Gwen Stefani and Blake Shelton

The "God Gave Me You" singer, 44, sweetly wrote in his caption that Stefani saved "the rest" of his life.

"Hey @gwenstefani thanks for saving my 2020... And the rest of my life.. I love you. I heard a YES!" he wrote, sharing the same photo.

Hours later, Shelton said on Twitter that he and Stefani "are extremely excited" to get married.

The pair — who have been quarantining in Oklahoma amid the novel coronavirus (COVID-19) pandemic with Stefani's sons Kingston, 14, Zuma, 12, and Apollo, 6 — have been known to join musical forces by collaborating on several duets. Their projects together include "Nobody But You" — which hit No. 1 on Billboard's Country Airplay chart — and "Happy Anywhere" from earlier this year.

Gwen Stefani and Blake Shelton
Gwen Stefani, Blake Shelton
| Credit: Harmony Gerber/Getty

They also dropped holiday song "You Make It Feel Like Christmas" and "Go Ahead and Break My Heart" from Shelton's 2016 If I'm Honest album.

Earlier this month, Shelton and Stefani won the CMT Music award for best collaborative video for "Nobody But You," a project that Shelton said "brought [them] closer together."

"We've been together now for five years, believe it or not," he told Entertainment Tonight after the win. "We've worked together and we've written together. So at this point in our relationship, we're always looking for what's the next thing that we haven't accomplished yet."