"Happy birthday to my favorite person I ever met @blakeshelton gx," wrote Gwen Stefani in social media, as a caption in a photograph of Shelton as a little boy.

The 46-year-old added a cow, bee and sunflower emoji with a hashtag of "superbabe."

The tweet was followed by a thank you tweet from the birthday boy: "Now THIS is how you start your 40's!!!!!!!" he wrote. "Thank you @gwenstefani for everything..."

Last November, their marriages had broken up, and the two came together. On Friday night, they stepped out to dinner in West Hollywood with Stefani's brother Todd and his wife, Jennifer.

"I just like being with her, but when she's all dolled up and we go places, it's always fun for me," he had said last month. "If she was here right now, not one person here would be looking at anybody else but her. It's just cool to know that's who I came here with. That's basically what [my new song 'A Guy With a Girl'] is about. They may come up and talk to me, but it's only because I'm one person over from her. Pretty cool."

Blake Shelton was part of Country Jam in Grand Junction, Colo on his birthday , Saturday night, June 18. Fans at the Country Jam were avid to know if girlfriend Stefani would be with him.

She was! Shelton declared to his fans that she had decorated his plane for his birthday.

He performed a two-hour set with Gwen Stefani.

At the end of the set, they sang "Go Ahead and Break My Heart," a duet that has been part of Shelton's 'If I'm Honest' album. And when the 46-year-old walked up on the stage, the crowd went wild.

He went on with hit numbers such as "Honey Bee", "Austin" and "Sangria." "Go Ahead and Break My Heart".

"This is fun!" he said. "Y'all have been so freakin' nice to me on my 40th birthday and I guess if I had one birthday wish for me personally ... I wish I could rock. I wish I was one of those artists that could rock but I can't."

"For my birthday I wish I could hear an artist who could rock, that's my birthday wish."

That brought Stefania on stage. She yelled "You want some of this?" and then played her band's song "Hella Good," asking her fans to jump for him. She then gave him a kiss and left him to finish his encore.

If Sheldon is thrilled to be with her, his fans are going ga-ga too. "Everyone is thrilled because they're both incredibly nice people," said an inside source. 

YouTube/Taste of Country