The four-hour gala raised a whopping USD six million to continue efforts to rebuild Haiti after it was hit by an earthquake five years ago, reported E!Online.
"It's essential support. At a certain point when there's a disaster or a conflict in an area, there are grant monies for organisations like ours but they dry up pretty quickly when you move into a development phase and so this particular night is essential to keep the work that we do going," Penn said.
The couple posed on the carpet for photographers and also shared a short kiss.
Clinton was not only a surprise guest, but he was also honoured by Penn. New parents Mila Kunis and Ashton Kutcher made a rare public appearance, but kept a low profile at a table in the book of the ballroom with Rachel Zoe and Soleil Moon Frye.
The other guests present at the charity gala were Chris Martin and Reese Witherspoon.