Season 9 of "The Voice" may be over, but Gwen Stefani and Blake Shelton's relationship appears to be going strong as they attended an engagement party over the weekend.

According to Us Weekly, the stars left Los Angeles together to attend singer RaeLynn's engagement party in Nashville on Saturday, Dec. 19. The website reports that Shelton threw the party for the singer, who is engaged to fiancé Josh Davis. RaeLynn was a contestant in season 2 of "The Voice" and was coached by the 39-year-old country star.

The 21-year-old took to Instagram to post pictures from the special occasion, and several snaps included Stefani and Shelton. One particular snap showed the country star with his arms around the No Doubt front woman as they posed with RaeLynn, Davis, and a friend and it was captioned, "Thank you @amandacraig12 and @blakeshelton for being the best hosts! Me and @josh_davis_18 are so thankful."

A source told E! News that the pair looked happy at the party.

"They were having a great time and dressed in spirit," said the insider. "Blake gave a nice little toast to RaeLynn and congratulated his close friend."

The two have been inseparable since the NBC showed aired its season 9 finale this month. Rumors of the two dating started making the rounds in October, and in November a rep of Stefani's confirmed that they are "longtime friends who have very recently started dating."  Last week, it was reported that the two have already met each other's parents.

According to People, the "Neon Light" singer introduced Stefani to his mother, Dorothy, during a recent trip to his home in Oklahoma. On Thursday, Dec. 17, the website reports that Shelton spent some quality time with the "Used to Love You" singer's father, Dennis, and a source said that the country star even helped him around the house.

"Blake helped Gwen's house around the house," said the insider to People. "They seemed very friendly and like they were getting along great."