BTS & Halsey have a secret handshake

BTS' RM and Halsey shared a cute moment behind the scenes of their new song 'Boy With Luv'.

The two made up their own secret handshake, which Halsey uploaded to social media.

Halsey became good friends with BTS around two years ago.

Commenting on their collaboration Halsey said: 'They have always been so creative and so concise. But this time they impressed me by how welcomed and at home I felt working on this collab."

"They are truly great artists and even better friends."

'Boy With Luv' has been smashing records online, becoming the fastest video to reach 100 million views.