Aldi is certainly enjoying its moment in the sun.

What was once a private and shy business is fast gaining ground as the mouthpiece for the discount grocer. Aldi's UK boss Paul Foley told Retail Week (August 29) that Aldi had reached the tipping point and been accepted into the mainstream supermarket sector. And while he maintained that the Aldi model would not change because it is a winning formula, this week he went further into the mainstream grocery sector by signing a celebrity to front its ad campaigns.

Celebrity chef Phil Vickery may not be Jamie Oliver, but he will take Aldi to another level. Like Oliver has done with Sainsbury’s, Vickery will work with Aldi on products and recipes as well as being the star of its TV campaign.

Aldi has stressed that Vickery has not received anything like the same fee as Oliver, but the concept is very similar. Vickery is daytime TV heaven for many consumers and Aldi is hoping that his celebrity status will pull in shoppers. Vickery's status as a chef is almost second to his fame.

Yet while the big four grocers fight it out with celebrities such as Oliver, Top Gear's Richard Hammond and even the Spice Girls, the discount grocers have always kept a low profile, concentrating on keeping costs down.

Aldi said that Vickery will review new products and work with the value grocer on new ranges. Yet, for Aldi, one of its cost efficiencies is that it doesn't have more than 1,000 products. Will Vickery's influence push up the number of lines in the stores? Or will he push some products out in favour of his own?

Vickery will appeal to certain demographic audiences, but will it propel Aldi onto a higher plain? The grocer has claimed that it is getting more ABC1 shoppers into its stores this year because of the credit crunch. But that demographic is trying Aldi because a neighbour or friend has told them it's actually good quality and they have less money to spend than usual.

It won't be Vickery that will draw in more ABC1 shoppers. If they were affected by celebrity advertising, then they would probably stick with Oliver.

It's understandable that Aldi wants to capitalize on the credit crunch and get as many UK shoppers to try it out while it can. But it needs to be careful not to lose its winning formula. Shoppers won't want to be paying Vickery's fees in their weekly shopping bills and, if they like a certain shepherd's pie or pizza at a certain price, they won't care if Vickery's stamp is on it.