LAS VEGAS -- A never-before-seen $1 million buy-in tournament at the World Series of Poker this year will generate the richest top prize in poker history at more than $12 million -- and potentially more if additional players get in.

Series officials planned to announce Thursday that 30 players are committed to participate in the Big One for One Drop starting July 1 in Las Vegas.

That number puts the top prize at $12.3 million, which is more than the $12 million Jamie Gold won in 2006 for beating more than 8,700 players at no-limit Texas Hold 'em in the $10,000 buy-in main event.

The final table will air live on ESPN, series spokesman Seth Palansky said. The winner will also earn a specially designed platinum bracelet.

Eight-time gold bracelet winner Erik Seidel has joined the field, along with the chief executives of a private college lender and a stock trading firm.

The field is a mix of high-stakes poker sharks known for their tremendous skills and wealthy businessmen for whom $1 million isn't much to spend. Of the 30 players in the field so far, only 10 are professional poker players.

Players like Johnny Chan, Tom Dwan and Daniel Negreanu are salivating at the chance to match up against lesser players, but billionaires like casino owner Phil Ruffin, and tournament organizer and Cirque du Soleil founder Guy Laliberte say they won't be as nervous with seven figures at stake.

The 30 confirmed players have already put up their buy-ins, and series officials expect to reach a cap of 48 entries. With that many players, the top prize would be $18.3 million.

The $1 million buy-in tournament includes a roughly 11 percent cut for charity but doesn't include the normal fees charged by the series for holding the tournament.

Laliberte organized the tournament with WSOP officials to raise money for One Drop, a non-governmental organization he founded that pushes for access to water in poor countries.