According to the source, the lovebirds arrived around 9:45 p.m. by a black SUV that Shelton was driving. The country crooner and his rocker girlfriend took a seat next to each other at a booth, and were "all over each other."
"They were very touchy feely," the source says, adding, "You could tell Blake was glad she was right there by his side."
The source also revealed that no one bothered the two as they sipped on drinks.
The No Doubt frontwoman and the "Boys 'Round Here" singer are back in town for a wedding, as Shelton's stylist, Amanda Craig, got married on Saturday. The bride is a celebrity stylist and co-owner of the Nashville salon, Leigh, Edwards & Company.
The wedding was a star-studded affair with Reba McEntire, Kelly Clarkson, Carson Daly and Dave Haywood of Lady Antebellum all in attendance. Shelton's former Voice contestant, RaeLynn, was also at the wedding, and took to Instagram to share a snap of the two ahead of the ceremony.
"Tradition nose picking pic," she captioned the black-and-white photo.
Shelton and Stefani were both in Nashville last month to celebrate RaeLynn's engagement to her fiancé, Josh Davis, with an ugly-sweater party planned by Craig and Shelton.