Kelly Clarkson's long-simmering feud with Blake Shelton just boiled over, a new report claimed.

On April 13, the country singer, 47, acted as the officiant as his manager, Narvel Blackstock,67, tied the knot with Laura Stroud in Nashville.

Narvel is the father of Kelly's ex Brandon Blackstock, 47, and is current locked in a
nasty multimillion-dollar legal battle with his former daughter-in-law, 41.

"It's a slap in the face. Kelly feels betrayed and is distancing herself from her former The Voice co-star. She doesn't want any unnecessary drama,” an unnamed insider told In Touch Magazine.

Ironically, Blake officiated Kelly’s wedding to Brandon. "At the end of the day, it's a tough spot for Blake to be in,” the informant went on.

Kelly Clarkson and Blake Shelton have yet to address the ongoing reports about their supposed feud. So, avid followers of the two Hollywood stars should take all these unverified claims with a pinch of salt until everything is proven true and correct.

Meanwhile, Kelly Clarkson celebrated her 42nd birthday with Heart's Ann and Nancy Wilson, who shared stories from the past and sang their great songs together, as per Rolling Stone.

During an episode of “The Kelly Clarkson Show” last week, Ann revealed that "Crazy on You" was the duo's "first song I ever recorded as a singer in a studio," and that while she "didn't have a bunch of technique" at the time, she "definitely felt how to say certain words."

Kelly then launched into a cover of the song while Nancy played her acoustic guitar.

The group also performed "Magic Man," which Ann stated was inspired by the first man she had "fallen head over heels in love with," and that her mother was "not thrilled with the idea of me running away with him to another country."

Kelly, Ann, and Nancy also performed their hit single "Alone," which was originally written by Billy Steinberg and Tom Kelly, recorded by Valerie Stevenson and John Stamos for the sitcom Dreams soundtrack in 1984, and then covered by the Seattle rock band for their 1987 album Bad Animals.

The Wilson sisters' version peaked at No. 1 on the Billboard Hot 100. Ann and Nancy made a kind gesture by giving the host a personalized leather jacket with their tour emblem on it.