@gwenstefani / Twitter 1 / 9
@gwenstefani / Twitter 1 / 9

Together for the holidays. It's bananas how serious Gwen Stefani and Blake Shelton have gotten. B-A-N-A-N-A-S.

Blake has already met the three children that Gwen shared with her ex, Gavin Rossdale, and he's already meeting her family. In fact, a source close to Gwen tells Wonderwall.com that the country superstar will spend Christmas with Gwen and company.

Then, after a brief stop in Arizona, where Blake is scheduled to sing the national anthem at the Cardinals game, the duo is set to head to Oklahoma, where they will ring in the new year with his family.

"He's been with her all week," the source said.

Last week, paparazzi pictures showed Blake hanging out with Gwen and her youngest child, Apollo. Other images showed Blake helping out Gwen's dad with a few boxes. Blake must know the key to Gwen's heart because, "her whole family is really, really close," the source said.

On Dec. 19, Blake and Gwen headed to Nashville for RaeLynn's engagement party.

Despite the new burgeoning romance, Gwen also wants normalcy for her children. According to E!, she and Gavin will likely spend Christmas morning with their kids, as to keep with tradition. Whether Blake will be there watching the kids unwrap the haul from Santa isn't known.

"It's very likely they will be together for some parts of it, but Gwen still wants to have the holidays as normal as possible because of her kids," the source told E! "So Gwen may do a more traditional holiday with Gavin when their kids open up the presents, but it's clear to her children they are not with each other in any romantic capacity."

The fellow "Voice" coaches began officially dating in early November after they both split with their longtime spouses. Within just days of their split announcements, rumors swirled the two were beginning to date. That speculation was confirmed by Gwen's camp as they two jetted off to Nashville so Blake could attend the CMA awards. It was the first time Blake and his ex, Miranda Lambert, were in the same room since their split.

Since Gavin and Gwen's split, Gavin has laid low amid rumors that he cheated on Gwen with their nanny. However, he returned to social media on Dec. 20, posting a photo from the Seattle Seahawks/Cleveland Browns game.

"The @Seahawks win!," a bundled-up and smiling Gavin captioned the image of he and three friends. Prior to the game day post, Gavin hadn't tweeted since Oct. 30. Nowhere to be seen was Mindy Mann, the nanny that Gavin supposedly cheated on Gwen with.