Sir Jackie has been working with RBS since 2004
Sir Jackie Stewart has agreed to waive any fees he would have earned this year from the Royal Bank of Scotland.
The former world motor racing champion works for RBS representing the company at events across the world.
The bank, which lost £24bn last year, said that Sir Jackie offered to fulfil his obligations in 2009 without pay.
Last month, tennis star Andy Murray offered to renegotiate his deal with the troubled bank which has supported him since he was 13.
RBS said that Sir Jackie wanted to help the bank with its new strategic objective of rebuilding standalone strength by serving its customers well, in the UK and globally, in the next three years.
Andrew McLaughlin, head of communications at RBS, said it was a tremendous gesture by Sir Jackie.
"He has worked tirelessly and with great success for the group over a number of years," he said.
"His commitment and loyalty at such a challenging time in the company's long history is greatly appreciated by everyone at RBS.
"Having his energy and talent focussed on our customers, charity partners and communities in the coming period will be our shared priority".
RBS announced in February that its 2008 loss totalled £24.1bn ($34.2bn), the largest in UK corporate history.
Sir Jackie Stewart's contract with RBS runs until 2011.
The new agreement means he will effectively provide three years' service to RBS for the price of two.
The bank said Sir Jackie's work with RBS supports every business division of the group.
This has involved a range of activities including the creation of new business, servicing of existing business and customer relationships, charity partner and community work as well as hospitality and sponsorship events.