D.C. Mayor Muriel Bowser forcefully pressed for D.C. statehood while casting votes at the Democratic convention on Tuesday in Philadelphia. (The Washington Post)

D.C. Mayor Muriel E. Bowser, speaking Tuesday at the Democratic National Convention, confidently predicted victory — and soon — in the District’s four-decade fight for statehood.

Bowser used the few moments she was allotted to address the convention to publicly demand greater support for the cause from fellow Democrats. The mayor also made clear that she expects Hillary Clinton to fulfill her pledge to be a vocal advocate for D.C. statehood if she wins the presidency in November.

Taking the microphone to announce D.C. Democrats’ overwhelming vote for Clinton to be the party’s nominee, Bowser introduced herself as mayor of “the best city in the world, and soon to be the 51st state of our great union.”

She also implored fellow Democrats to help in the fight: “We are 670,000 tax-paying Americans, just like you. And with statehood and only with statehood, will we have votes in Congress, just like you,” Bowser said. “The next president of the United States, Hillary Rodham Clinton, will sign our admission into the United States of America as the 51st State.”

Bowser’s proclamation came hours after she and D.C. statehood advocates hosted a luncheon atop a hotel near the convention hall that attracted over 60 delegates and 15 celebrities. It was a much better turnout than at the Republican convention last week, when only one Republican delegate attended a similar reception in Cleveland.

Dean Norris, of “Breaking Bad,” tries on a tricorne 51st state hat passed out by D.C. statehood advocates at the Democratic National Convention. (Jabin Botsford/The Washington Post)

As in Cleveland, the contingent from Hollywood was already at the convention lobbying for funding for the arts. Members of the group, including William Baldwin, Ashley Judd, David Schwimmer, and stars of “Orange is the New Black,” “Newsroom” and “Breaking Bad,” have lent their start power to the statehood effort.

Bowser, D.C. Council Chairman Phil Mendelson and the District’s nonvoting “shadow” delegation spoke at the luncheon. They rehashed familiar arguments, such as the high federal taxes paid by D.C. residents, to make their case that it is past time for D.C. to be granted statehood.

But with the celebrities in attendance, the arguments, at least briefly, gained a broader audience than usual. The actors and actresses in attendance had a combined 9 million Twitter followers, or 13 times that of the population of D.C., and even larger bases on Facebook and some other social media platforms.

“We need to take this debate nationwide — and this is a chance to highlight and bring the issue of statehood to larger national attention,” said Shadow Sen. Paul Strauss, who has begun an effort to film commercials with 51 celebrities in favor of D.C. statehood. “These folks can touch people and take our message to people I and others in D.C. cannot.”

Asked about the cost to D.C. taxpayers, Strauss said he could not immediately break down the expense but said it was minimal. The luncheon cost “a couple thousand dollars,” he said, and was underwritten mostly by the nonprofit D.C. Vote. Some money would eventually come from a city fund used to advocate for statehood, Strauss said,

The event also drew some unexpected support from rising Democrats. The party’s nominee for Pennsylvania attorney general stopped by the event and took the podium to express solidarity with D.C. The candidate, Josh Shapiro, said the District’s fight for voting rights in Congress reminded him of a battle with Republicans over voter ID laws in Pennsylvania in recent years.

“I know I am preaching to the choir,” Shapiro said. “But this is not just your battle, it’s our battle. It’s America’s battle.”

Actress Troian Bellisario appears at a D.C. statehood luncheon during the second day of the Democratic National Convention. (Jabin Botsford/The Washington Post)