Gwen Stefani

Gwen Stefani and Blake Shelton have both been all smiles since taking their relationship public, and there's a reason for that.

A source tells E! News exclusively that the No Doubt singer and the country crooner are getting more and more serious as they continue their relationship. The Voicecoaches have fully immersed each other into their personal lives and it has been doing incredibly well.

"Gwen and Blake are steaming up," the source says. "They have been having some great times with each other the past few months and are on the same page of life now. Blake is extremely supportive of Gwen and her kids' transition. Blake is really great with kids and loves being around children. He has a lot of patience."

The couple "spend a lot of time together" and are "getting more serious," the source adds. They even jetted to Nashville over the weekend to celebrate theengagement of singer RaeLynn and Josh Davis, where they "had a blast," another source dishes to us.

"They were extremely friendly to everyone at the party and fit in just great," the other source says. "They acted normally and were very down-to-earth, regular people. Both of them together were the life of the party. They didn't show too much PDA, but you can tell they were a couple and very into each other."

At the party, which Blake helped plan, Gwen and the "God Gave Me You" singer really enjoyed themselves and loved helping RaeLynn celebrate her big day, an insider dished to us. "Blake and Gwen were great. They looked happy. They were having a great time and dressed in spirit," a source told E! News. "Blake gave a nice little toast to Raelynn and congratulated his close friend…what a friend would do for another friend."

Guests enjoyed appetizers such as crab cakes, double-stuffed new potatoes, hush puppies and more at the private event and catering venue. Photobomb Nashville provided the photobooth and guests competed for Best Dressed in the Ugly Holiday Sweater contest.

"Everybody was having a good time," our source added.

Gwen and Blake will be spending parts of Christmas together, as Gwen wants her kids to spend time with their father, Gavin Rossdale.