Blake Shelton's ex-wife, Miranda Lambert, recently dissed him on stage while singing "Little Red Wagon" by changing her lyric, “I live in Oklahoma” to “I got the Hell outta Oklahoma.”

Following the surprising diss, which quickly caused a stir on Twitter, a source claims Shelton and his new girlfriend, Gwen Stefani, who he began months after his July 2015 divorce from Lambert, are unconcerned about his ex-wife's antics.

“Blake had his own songs and conversations after separating with Miranda and Miranda has her similar journey as well but Gwen and Blake really are interested in letting go of Miranda Lambert and what she says or does moving forward,” a source close to the couple told Hollywood Life on Jan. 23.

While Lambert's diss may have been mean-spirited an unnecessary, the insider said that Shelton and Stefani know better than to be looking back on past relationships, especially because they are so happy in their current relationship with one another.

“They are still in love, they are in a wonderful relationship and they just want to have it be their relationship,” the source continued.

Shelton and Stefani went public with their relationship in November 2015, just months after Shelton confirmed that his marriage to Lambert was coming to an end after just four years. Two months later, Lambert confirmed her own romance with fellow musician Anderson East, who she is still dating.

The Hollywood Life source went on to reveal that Shelton and Stefani are refusing to think or talk about their exes, including Stefani's former husband, Gavin Rossdale, because it simply doesn't benefit them to do so. Instead, they are keeping their past in the past and focusing on their romance and future together.

Stefani shares three kids, 11-year-old Kingston, eight-year-old Zuma, and three-year-old Apollo, with Rossdale, who she was married to for 13 years.

In the coming months, Shelton will return to production with NBC for the upcoming 14th season of The Voice. As some may have heard, Shelton and his longtime co-star, Adam Levine, will be joined by returning cast member Alicia Keys and new coach Kelly Clarkson.

Although Stefani has starred on the show during past seasons as a coach, she hasn't appeared on The Voice since season 12 and has no confirmed return date to the show.

The new season of The Voice will premiere on NBC on Feb. 26 at 8 p.m.