AceShowbiz -

Blake Shelton was photographed kissing his girlfriend Gwen Stefani during a romantic date night in Studio City, California on Tuesday night, December 8. The couple couldn't keep their hands off each other.

In some photos obtained by E! News, the "Hollaback Girl" hitmaker was seen smiling widely while the "God Gave Me You" crooner smooched her lips. The pair donned matching outfits with Gwen wearing a washed-out denim shirt and pants and Blake sporting a black shirt and jeans. They were waiting for valet outside the Casa Vega Mexican restaurant.

An onlooker told the site, "They were there with another couple and were waiting for valet for about five minutes. He kissed her twice and was pretty much grabbing her butt as he did." The source added that while they waited, "He was square dancing to amuse the group, and Gwen joined in for a bit, too."

Blake and Gwen looked "cozy" and in "high spirits" during their dinner date, sitting close the entire time. "They were sitting at the bar and were very affectionate during dinner," the source said. "He had his arm around her, [and] they had margaritas. After dinner they left together and went to her house." Another source claimed the pair were "good customers and wonderful people."

On Monday, Gwen took to Twitter to share a PDA photo with Blake. The snap, featuring the couple, and fellow "The Voice" coaches Adam Levine and Pharrell Williams, showed Blake bitting Gwen's shoulder as she was smiling at the camera.