Jamie Oliver has signed a new one-year contract to continue being the face of Sainsbury's advertising campaigns.

Oliver has fronted advertising campaigns for the supermarket for the last three years. Neither party has commented on the value of the contract, though his last one-year contract was thought to be worth at least £500,000.

The deal comes at a vital time for the group with Sainsbury's currently struggling to hold its position within the grocery market.

Sainsbury's has used Oliver as part of its business transformation and his contract includes working as a consultant to the group and assisting in such areas as product development and staff training. This role will continue under the terms of the new contract.

According to a recent study the £41 million spent on campaigns using the chef has brought the company an extra £1bn in sales. Sara Weller Sainsbury's deputy managing director said Oliver remained an ideal partner for the group.