The 50g cereal-based bar will be the latest extension of Lucozade Sport range, which currently includes an isotonic drink and a 'carbo-gel' energy boost product.
The bar, which is high in carbohydrate and protein but low in fat, will be introduced into specialist retailers such as Boots in Q1 2003, with a mass-market launch in Q2.
"The product will be marketed according to need states - such as sporting occasions - rather than as a snack food," said Peter Harding, marketing director for GSK consumer healthcare.
Lucozade Sport, which launched in 1990, continues to dominate the UK sports drink market, but is facing growing competition from Coca-Cola's Powerade and PepsiCo's Gatorade brands.
Harding said the Lucozade Sport range will get a boost in adspend during 2003. GSK spent £3.2m on the range during the past year, according to Nielsen Media Research. The ad account is up for review out of Ogilvy & Mather.