Karl Stefanovic and Hugh Riminton have lashed out in a bitter public feud.
Stefanovic endorsed a Barrier Reef charity, Great Barrier Reef Foundation, on Sunday, and Riminton claimed the 43-year-old television host had no 'journalistic principles.'
Karl wrote to Twitter, 'The @GBRFoundation deserves and will use every cent in its arsenal to save the reef.
'I’ve no doubt their research into reef DNA and conservation is the key. Let’s give them supporting space to prove it.'
Twitter users were quick to notice that Karl's intentions may not have been genuine, with the Great Barrier Reef Foundation being a sponsor for the Today Show's We Love Australia trip last year.
Hugh Riminton tweeted a response to the Today host, questioning his 'principles'.
Hugh addressed Karl directly, writing: 'Dear Karl, might it have been appropriate to mention that @GBRFoundation has been a TODAY show event sponsor? There is some strength in old principles.'
Karl replied: 'Dear Hugh. There is some strength in old journalistic principles as well. To my knowledge no foundation funds have ever been used in a Today Show OB. Thanks for checking. Long live the reef.'
Karl then addressed his followers, tweeting the only concern was for the Great Barrier Reef.