Lovato's producers previously denied a sampling, but a complaint filed on Monday asserts that similarities "transcend the realm of coincidence."

Pop star Demi Lovato is now facing an allegation of infringing the work of Sleigh Bells, one of the most successful indie rock bands of the past few years.

In a complaint filed Monday in California federal court, Sleigh Bells members Alexis Krauss and Derek Miller allege that Lovato's "Stars" contains material taken from their 2010 track "Infinity Guitars" off of their debut album. The lawsuit names Lovato, UMG Recordings and producers Carl Falk and Rami Yacoub as defendants.

"A comparison of the two songs reveals that, at the very least, the combination of the hand claps and bass drum, structured as 3 quarter beats and a rest, with the bass drum providing a counter-rhythm to the hand claps, is at least substantially similar in both works," states the complaint. "This infringing material repeats throughout the Defendants’ song."

The complaint also alleges that "signal decay and other sonic signatures" reveals "virtually identical content" and "transcend the realm of coincidence."

Sleigh Bells' debut album Treats was critically hailed and ended up on the top 10 lists of many publications. It peaked at No. 39 on the Billboard 200. "Infinity Guitars" was the second single from the album and made Rolling Stone's list of the best songs of the year. The song also was licensed to Samsung for a commercial. This could be important to the litigation as a high degree of access typically means a lower standard of proof of substantial similarity.

Lovato's "Stars" appeared as a bonus track on her fifth album, Confident.

Upon that album's release in 2015, Sleigh Bells tweeted, "Demi Lovato flattered you guys sampled Infinity Guitars & Riot Rhythm for 'Stars' but we were not contacted. Gotta clear those."

At the time, Lovato's reps denied using the Sleigh Bells track.

"We did not use any samples in Demi Lovato's song 'Stars.' Demi was also not involved with the production," producer Carl Falk and Rami Yacoub said through Lovato's reps. "She only wrote top line."

Here's the full complaint, plus the two songs for comparison: