The Aussie pair, who are more commonly known as Merrick and Rosso, split after Ross decided against signing a new deal with Nova radio station to continue hosting their show with ex-Home and Away star Kate Ritchie.
An industry source told The Daily Telegraph that the DJ made his decision following a "turbulent" meeting with management last week.
It is believed that Watts will return to the station without his partner, but it is unknown whether Ritchie will stay on as his co-host.
Ritchie joined the two on their long-running programme after quitting her 20-year stint as Sally Fletcher in the Australian soap.
