William Hill U.S. will operate the first sports betting venue inside a U.S. sports arena through a deal announced Thursday with Monumental Sports & Entertainment, owners of the Capital One Arena in Washington D.C.

The Las Vegas-based company will build a sportsbook inside the arena, home to the NHL’s Washington Capitals, the Washington Wizards of the NBA, and the WNBA’s Washington Mystics, pending regulatory approval. The sportsbook will be operational when the arena is not is use through a sports bar that is attached to the facility.

During game days and certain in-arena events, ticketed and non-ticketed fans will have access to the sportsbook. The sportsbook also will be open on non-event days. William Hill’s mobile sports betting app will be available to sports fans for wagering inside the arena during games, as permitted by the Washington D.C. regulations.

“This sports book will be a flagship venue for the industry and will serve the sports fans of the Washington D.C. area unlike any other,” William Hill US CEO Joe Asher said in a statement.

Monumental CEO Ted Leonsis said this year his goal was to put a sportsbook inside the arena, which is near Washington D.C.’s Chinatown and is adjacent to the city’s busiest Metro stop. He purchased a tavern adjacent to the arena to convert into a sports bar.