Their alleged liaison happened at the Costa Galana Hotel in Mar del Plata – 250 miles from caspital Buenos Aires.
Legrand was on TV programme La Noche De Mirtha when she made the stunning claims dating back to 2006.
“I was in the presidential suite, next to them and I couldn’t sleep because of the noise.
“They moved furniture, I don’t know what they were doing. This is the truth.
“I was an auditory witness to their rampant sexual encounter.”
Nara, 31, was married to Icardi’s former Sampdoria team-mate Maxi Lopez before divorcing him and marrying his pal.
She has three sons with Lopez and two daughters with 23-year-old Icardi, who she has been with for four years.