BTS and Justin Bieber are rumoured to be working on a collaboration.

According to an insider, the K-Pop boy band - comprising RM, Jin, Jimin, J-Hope, Jungkook, V and Suga - have been preparing a song with the 'Peaches' hitmaker, which may feature on another deluxe edition to his latest album, 'Justice'.

A source told The New York Post‘s Page Six column: “They are taking their time on it and going to make sure it is released right.”

The pop megastar has already released ‘Justice (Triple Chucks Deluxe)’, with special guests Jaden Smith, Tori Kelly, Quavo, Lil Uzi Vert and DaBaby.

Meanwhile, the 'Dynamite' hitmakers will return with their new single, 'Butter', on May 21.

The Korean septet's second English-language single, following 2020's mega-hit 'Dynamite', is described as a "dance-pop track brimming with the smooth yet charismatic charm of BTS".

It's not known if it will be a standalone single or whether it will be part of an upcoming EP or album.

The boy band had record-breaking success with their very first all-English track.

With 'Dynamite', BTS became the first Asian act ever to debut at the number one spot on the Billboard Hot 100 chart in the US, with a debut sales week that outsold every track released in the last three years.

The song also broke multiple streaming records on Spotify, iTunes, and YouTube, and earned the group their highest-charting single in the UK when it debuted at number three.

The 'IDOL' band also became the first K-pop act to receive a major Grammy nomination, although 'Dynamite' lost out in the Best Pop Duo/Group Performance category to Lady Gaga and Ariana Grande's collaboration 'Rain on Me'.