NEW YORK (CNN/Money) - Coca-Cola Co., the world's biggest soft drink group, may be planning a new variation of its winning formula, according to a published report.

Not satisfied with the century-old regular Coke -- or the more recent diet and cherry-flavored spinoffs -- the U.S. bottler is reportedly working on secret plans for a vanilla version.

An article in industry newsletter Beverage Digest said numerous people within the company expected a U.S. launch of a vanilla-flavored Coke "within the next few months.''

Coca-Cola officials are keeping a tight lid on things, telling the London-based newspaper that "we've always got a number of things in development."

If true, the launch of the new product would be the biggest since the company's infamous introduction of New Coke in 1985, when the company -- facing pressure from rival PepsiCo (PEP: down $0.38 to $51.12, Research, Estimates) -- altered its 99-year-old traditional recipe for a sweeter product.

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But New Coke quickly fizzled, and the company returned to its original recipe, reintroducing it as Classic Coke.

It had more success with its Cherry Coke, which was also launched in 1985.

Coca-Cola (KO: down $0.56 to $51.70, Research, Estimates) said earlier this month it expected sales volumes to grow between 4 percent and 5 percent in the current quarter.

The improved performance is due mainly to strong demand in its key North American market, which is starting to recover after years of flat growth.