Hurricane Irma and Harvey Telethon Draws Huge Stars on Live 17-Network Broadcast

The telethon to raise money for victims of Hurricanes Irma and Harvey has picked up steam, and could be one of the biggest ever of its kind when it hits the air tomorrow night.

The list of celebs is super impressive. TMZ has learned of the new names added to the show, which will air Tuesday between 8 - 9 PM. The celebs include Al Pacino, Justin Timberlake, Travis Scott, Dave Matthews, Jon Stewart, Chris Paul, Demi Lovato and Diddy ... oh, and Leo DiCaprio.

The new additions will join Justin Bieber, Drake, Reese Witherspoon, Jamie Foxx, Blake Shelton, Billy Crystal, Robert De Niro, Sofia Vergara, Michael Strahan, Tim McGraw and Faith Hill.

A number of the celebs will be manning the phones and taking donations. There will also be performances. The show will be live from L.A., NYC and Nashville.

We're told Michael Dell and Verizon are underwriting the entire event so 100% of the money will go to help the hurricane victims. What's more, Dell will match the first $10 million. Apple is donating $5 mil.

And, as we reported, the big 4 networks -- CBS, NBC, ABC and FOX will all carry the show live. Now we're told there will be 17 networks in all running the telethon, including MTV, BET, CMT, Bravo, Oxygen, Univision, HBO, Facebook, Twitter and YouTube.