It is grown in Spain and is the product of 12 years of trials, the retailer said.
It has 700/800mg of citric acid per 100g - almost twice that of a standard melon - and a pH level of 4.5 compared with 6.5 for a standard melon.
"The lemon melon causes a great reaction when people first try them because the last thing you expect from a smooth-textured melon is a tangy aftertaste," the Daily Express quoted Tesco melon buyer Paul Cunningham, as saying.
"We believe that they will become the culinary hit of the summer once people have tasted them.
"The lemon melon tastes great chilled as either a starter served with prawns or as a dessert," he added.
The melon goes on sale tomorrow at Tesco stores for 1.99 pounds each.