Pena often broke out in song to keep up the spirits of the miners trapped underground. And it turns out he also can sing duets.
He joined Newton-John on the song "Summer Nights" from the musical "Grease" and got a big ovation.
Pena met Newton-John on a Chilean talk show the night before and she asked him to join her on stage Monday night before 10,000 fans.
Pena said "being on stage was incredible."
To view a YouTube video of Pena's performance click on the player below.