Why billionaire Andrew Forrest's wife Nicola wears her son's decade-old hand-me-down RM Williams boots despite OWNING the company - and still washes and reuses ziplock bags 

•  Nicola Forrest has been married to billionaire Andrew Forrest for 30 years  
•  The pair founded philanthropy juggernaut the Minderoo Foundation in 2001 
•  Mrs Forrest has revealed she is driven by frugality, humility and hates waste 
•  She still wears her son's decade-old RM Williams boots and reuses ziplock bags 

Billionaire Andrew 'Twiggy' Forrest's wife has opened up on why she wears her son's old RM Williams boots despite owning the company. 

Nicola Forrest, mother-of-three and philanthropist, has been married to mining magnate Mr Forrest for 30 years but doesn't believe in splurging their wealth. 

Mrs Forrest said she is driven by frugality and humility and strives to hold the couple accountable for their own impact on the earth. 

'People assume it's all Hollywood and it's really not,' she told the Sunday Times Magazine.

The Forrest's eldest daughter Grace said Mrs Forrest is so passionate about the environment she avoids waste wherever possible. 

Mrs Forrest has even kept the well-loved pair of RM Williams boots her son Sydney wore until he grew out of them at 10-years-old.

'He is 20 now and she still wears them, it's hysterical,' Grace said.

Her mother's hatred of waste led Mrs Forrest to abstain from using cling wrap and to wash and reuse plastic ziplock bags. 

Mrs Forrest explained others often made assumptions about herself and her family because of their fortune.

'When my kids were at school and you'd get to know the other parents bit by bit, they would say, "oh, you're just like a real person" and I would just say, "what did you think?",' she said.

Mr Forrest built his fortune in mining by founding Anaconda Nickel Ltd, now known as Minara Resources, in 1994, before founding Fortescue Metals Group in 2003. 

Mrs Forrest said she agreed with Mr Forrest that once they 'got to a certain point' in the business earnings they would 'give the rest away'.

The Forrests founded Minderoo Foundation in 2001 and made record-breaking donations of $400 million in 2017 and $655 million in 2019. 

The foundation's core initiatives include reducing disparity between Indigenous and non-Indigenous Australians, cancer research and fire and flood resilience.   

Mrs Forrest explained the couple were motivated by 'creating opportunities' and were 'very much driven' by their rural upbringings.  

The mother-of-three also said she was proud to have raised 'healthy, functioning children who are giving back'.

Their son is studying at university while Grace heads the Walk Free foundation and their other daughter, Sophia, is an actress.   

Mr Forrest has an estimated net worth of $15 billion and is consistently named in Australia's top 10 richest people.