Gwen Stefani and Blake Shelton Attend Midnight Christmas Mass Together Amid Wedding Rumors

Gwen Stefani and Blake Shelton attended a Christmas Eve Mass together on Tuesday as rumors swirl that they're getting ready to tie the knot. The famous duo was spotted heading into St. Brendan's Catholic Church in Los Angeles, a source told RadarOnline.com, looking closer than ever.

"Gwen and Blake held hands and were so sweet with each other at the church. They hugged and kissed during the peace offering," the source said. "Both were generous with their giving at the service and Blake even handed money to her older son Kingston to put in the basket."

The No Doubt songstress and Shelton "of course sang along with the other worshippers to the Christmas carols," the source said, adding that Stefani, 50, and Shelton, 43, looked like a happy family while celebrating Christmas.

"She held her son Apollo in her arms during the service. It was cute," they said, adding that Apollo "looked adorable in a black and white striped blazer, all dressed up for Christmas."

Fans of the power couple have been speculating about a possible wedding, though a religious conflict has reportedly kept them from the altar, with a source telling PEOPLE recently that in order for them to get married in the Catholic church, Stefani will have to have her previous marriage to rocker Gavin Rossdale annulled.

"Blake was very serious about Gwen right from the start, and early on he thought about proposing," the source said.

Stefani and Rossdale were married from 2002 until their split in 2016.

As for Shelton and Stefani's Christmas plans, Shelton previously told Entertainment Tonight that they were "going to do Christmas here in the wintry hills of Los Angeles" and that they'd head to his Oklahoma ranch after Christmas Day. "I have not been handed the schedule yet. I just know that I am going to be a part of whatever is happening," he said.

The two, along with their extended families, spent Thanksgiving in Oklahoma at Shelton's home.

"We all fly out to Oklahoma, like 30 of us," Stefani previously told the outlet. Blake has this bed and breakfast hotel that we all stay at, and it's just pretty incredible. We have fun, we all cook together. It's fun."

"This'll be … I wanna say the fourth [year], but it might be more than that," Shelton added. "We're taking all the Stefanis and then the Shelton bunch are gonna meet up there and just literally [spend] like, five days away."

Shelton and Stefani just wrapped up Season 17 as coaches on The Voice. Stefani will be replaced next year by Nick Jonas.