Justin Bieber is set to tour with Ariana Grande.

The 'What Do You Mean?' hitmaker is gearing up to release his new album next month and is planning a worldwide arena tour on which Ariana will join him for several dates in the US.

A source revealed: ''The whole thing will hopefully end in several (U.S.) stadium dates with special guest Ariana Grande.

''This is in the very early stages but serious conversations are taking place.''

The 21-year-old star will reportedly open the show and perform several songs with the 'Problem' singer, as they have previously done during her 'Honeymoon Tour'.

The source continued: ''They would both perform their solo hits then team up together for several duets.

''It's Justin's tour, so he would open the show. Then they can decide what they'll perform together and what they'll do solo. They'd likely unite at the end of the show for a hit.''

And organisers are hoping securing Ariana to join Justin at the shows will bring in extra guests as lots of his fans also love the brunette beauty.

The source told the New York Daily News newspaper: ''There is a ton of crossover in their fan base.

''If it does happen, it will be the top tour of 2016, pulling in hundreds of millions for the two singers.''