James Packer has stepped down from the board of private family company Consolidated Press Holdings, just four months after quitting the board of casinos operator Crown Resorts.
A CPH spokesperson says Mr Packer left the CPH board within the last fortnight as he "continues his recovery" - a reference to the mental health issues that led to his departure from Crown in March.
No further details were available on Monday.
CPH - Crown's largest shareholder with a 47.2 per cent stake - said in March that Mr Packer was suffering from mental health issues.
It was understood at the time that Mr Packer's decision to resign from Crown was sudden and made independently after he realised he had been unwell for some time.
At the time, Mr Packer was in the US and intended to take a complete break from work commitments to regain his health.
The billionaire, who was engaged to American singer Mariah Carey for nine months in 2016, had only taken up a Crown directorship in August 2017 having resigned from the board almost two years earlier.