The announcement that Penn would deliver his remarks during the 9 pm to 10 pm slot tonight came soon after the Obama Campaign announced yesterday that the Indian American actor would host the Democratic National Convention's official live stream prime-time coverage on Thursday.
It is the first time that the Democratic convention has involved live stream coverage.
Penn, whose original name is Kalpesh Suresh Modi, featured in a video advertisement released by the Obama Campaign.
In this video, President Barack Obama is seen making a telephone call to Penn, former Associate Director of the White House Office of Public Engagement, and asking him to take his job "of hosting the live coverage" seriously.
"Hey, this is Barack," Obama says. "Listen, I need to know if you're on board. Okay, good. Because I'm counting on you. Everybody is. We have to get this right. So there's a lot at stake here.
"Just remember that I'm trusting you on this and I'll see you then," the President said, at the end of which the video shows the shots of Penn sitting on a couch along with his friend John Cho, the actor who played his stoner companion Harold in the "Harold And Kumar".
"Dude, who was that? That sounded intense," says Cho as he shovels cheesepuffs into his mouth. "The President," Penn says with a blank stare and no enthusiasm "Sweet," says Cho.
Moments later, both devolve into laughter at the cartoons they're watching.
The video is promoting "Live From Charlotte," a web-only convention special that Penn will host on Thursday at 8 pm.
The programme will have interviews with celebrities including Marc Anthony, Elizabeth Banks, Aisha Tyler, Olivia Wilde, Fran Drescher, Zach Braff and Alexis Bledel.
In addition to Penn, another Indian-American Kamala Harris would appear on the first day of the Democratic National Convention. Harris, Attorney General of California, would make presentation during the opening ceremony in her capacity as the co-chair of the rules committee.
Tulsi Gabbard, who appears all set to become the first Hindu-American to enter the US House of Representatives, would also deliver remarks in the time slot of 7 pm to 8 pm along with Democratic Leader Nancy Pelosi.
In the recently-concluded Republican National Convention in Tampa, South Carolina Nikki Haley made history by becoming the first Indian-American to deliver a prime time address.
Congressional candidate from California Ranjit Ricky Gill, 25, too addressed the convention; while Bobby Jindal, the Louisiana Governor, had to cancel his address to because of hurricane Isaac that hit his State.
History was scripted when a Sikh, Ishwar Singh, offered invocation on the second day of the convention.