Tesco, Britain's biggest grocer, said Alan Stewart, will join the firm as chief financial officer from today, rather than the previously announced date of December.
Stewart quit from the same role at Marks & Spencer on July 10 to join Tesco but had since been on a period of so called "gardening leave".
Tesco wanted to get Stewart early after revealing on Monday an accounting issue that had led it to overstate its first half profit forecast by £250m (€318m).
More than £2.2bn (€2.8bn) was wiped off Tesco's market capitalisation on Monday as it counted the cost of an accounting scandal that has rocked investors.
The giant grocery retailer - Ireland's biggest and the world's third largest - revealed that it had discovered a £250m (€318m) error in its accounts, after over-stating first-half profits.
Its shares plunged over 13pc at one point.
Newly-appointed chief executive Dave Lewis described the financial black hole as a "serious issue".
It means that profits for the first half of Tesco's financial year - which ended on August 23 - will be about £850m (€1.08bn) rather than the expected £1.1bn.
Four senior executives were immediately placed on leave by Mr Lewis until a probe that headed by tax firm Deloitte and legal advisers Freshfields is completed.
The four key employees asked to step aside while the investigation is underway include the head of Tesco's UK business, Chris Bush.