Purity rings, gay bars, and busking on Carpool Karaoke

Demi Lovato, Nick Jonas and James Corden get "Close" on Carpool Karaoke.

Another episode of Carpool Karaoke has landed, this time featuring best friends Demi Lovato and Nick Jonas.

James Corden kicks things off by immediately questioning their relationship, asking if they've ever been romantically linked - they haven't - before delving into the ins and outs of Jonas' love life including endlessly mocking his purity ring.

James Corden's audition to join Demi and Nick on tour.

They sing Lovato's Heart Attack (complete with Corden and Lovato acting out what a heart attack would look like) some old-school Jonas Brothers and even arrange a three-way harmony to Jonas' Jealous.

They talk crazy fans and sing Jonas' Chains before Corden asks, "have you ever been tied up?" to which Jonas responds with an anecdote about being chained up in a gay club.

And as Corden is hoping to join the pair on tour, they hold an audition on the side of the road in front of a full tour bus.

You can watch the full clip here: