It sounds like Dan + Shay are in for 10,000 headaches.

Dan + Shay and Justin Bieber are named in a lawsuit filed Thursday over copyright infringement of their chart-topping hit "10,000 Hours."

People reported that International Manufacturing Concepts, Melomega music and Sound Gems sued Bieber, Dan + Shay, and others due to similarities in "10,000 Hours" to the 1973 song "The First Time Baby Is A Holiday," written by Palmer Rakes and Frank Fioravanti.

The suit states the men "stole the core portion," which includes the chorus, verse and hook from "The First Time Baby Is A Holiday." "The First Time Baby Is A Holiday" was written in 1973, not registered until 1980, and was recorded in 2014 when it was re-registered because they slightly changed the song title.

"10,000 Hours," which also includes co-writers Jessie Jo Dillon, Jordan Reynolds, and Jason "Poo Bear" Boyd, was released in 2019 and is from Dan + Shay's "Good Things" album.

The suit alleges there are "unmistakable similarities."

Reps for Bieber and Dan + Shay did not immediately respond to People's request for comment.

Lawsuits aside, Dan + Shay are gearing up to help Kenny Chesney launch his Here And Now 2022 stadium tour presented by Blue Chair Bay Rum and fueled by MARATHON, Saturday at Tampa's Raymond James Stadium. Old Dominion and Carly Pearce will also join Chesney on tour.