The production of Wispa bars was halted in 2003 due to poor sales in the 1990s but Cadbury agreed to bring it back in August last year for an unspecified limited period after thousands of people joined groups dedicated to the aerated chocolate bar on sites such as Facebook, MySpace and Bebo.
Cadbury said that 20m bars were sold in seven weeks during a trial run last year and that the bar will be back on full sale on October 6 at a cost of 45p.
It was 16p when it was first introduced in a trial in the North East in 1981 and was seen by many as a rival to Nestle's Aero.
User-generated campaigns set up to bring about Wispa's return included a Bebo group called "We Like Wispa", and a YouTube video of the brand's TV ads, featuring Victoria Wood, Julie Walters and Windsor Davies under its strapline "Bite it and believe it".
Tony Bilsborough, a spokesperson for Cadbury, said: "Wispa is a true icon loved by its fans everywhere. We brought it back temporarily to see if the desire was genuine, but fans are still rallying so we took the decision to bring it back for good.
"We know others have looked at the Wispa and tried to copy its success by bringing back other brands, but we don't believe that anyone has managed to recreate the same excitement."
In May this year it was revealed that Marathon bars are set to make a comeback 18 years after confectioner Mars renamed them as Snickers. Mars has also announced plans to bring back Opal Fruits, which were renamed Starburst 10 years ago.