The 24-year-old, who played at the Estadio da Luz for four years, has cut short his summer break in order to play against his former side in a friendly match on Friday
After joining Madrid for €30 million from the Eagles in 2011, Coentrao played every minute of Portugal's journey to the European Championship semi-finals, and he admitted his excitement at facing off his against former club.
"Being able to return to what was, and remains, my home is always something very special," he told A Bola. "I am delighted. It is true that I lose a vacation day, but worth it because it will be a very nice meeting, both for Real Madrid and Benfica."
And the left-back offered his sympathy to Eusebio, who was hospitalised after suffering a stroke while watching the Seleccao during Euro 2012.
"I know what happened, but I'm sure he will recover. He is not just part of Portugal's heritage, but also of world football's."