The 27-year-old German, who will also contest the six-hour World Endurance Championship race at Spa as preparation for his Le Mans bow, said the desire to compete in both disciplines had been too alluring to turn down.
"Porsche and Le Mans - this combination probably attracts every race driver," said Hulkenberg of the twice-round the clock race, which in 2015 takes place on June 13-14, the weekend in between the Canadian and Austrian Grands Prix.
"I've been a Porsche fan for a long time and have been watching their return to the LMP1 class closely. The desire grew to drive that car at Le Mans."
Hulkenberg also thanked Force India for allowing him to race at Le Mans, adding: "I am very pleased the 2015 Formula One calendar allows for it and I'm grateful to my Sahara Force India Formula One Team's generosity to let me go for it.
"Now it's up to me to work hard to satisfy both commitments."
Though it was common in the past, the last driver to compete in both Grand Prix racing and the Le Mans 24 Hours at the same time was Sebastien Bourdais, who raced for Toro Rosso and Peugeot in the respective disciplines in 2009.
Four drivers in history have won both the Formula One world championship and the Le Mans 24 Hours overall - Mike Hawthorn, Phil Hill, Jochen Rindt and Graham Hill.