Venerable talk show host Larry King, hip hop mogul Russell Simmons, ice cream icons Ben and Jerry and presidential daughter Barbara Bush all stepped forward in New York, making attention-grabbing appearances in a long-running ad campaign.

A similar effort got underway Monday in Maryland, with no pretense of matching New York’s star power but with the same aim: building support for the legalization of same-sex marriage.

“I’m Gov. Martin O’Malley, and I’m a Marylander for marriage equality,” the state’s chief executive says at the top of the campaign’s first Web video.

Organizers vow to produce a steady stream of other supporters — including athletes, clergy, law enforcement officers and other well-known politicians — from now until the Maryland General Assembly votes on the issue again next year.

The ad campaign comes as both sides, including church groups that oppose same-sex marriage, gear up for a legislative rematch in January on one of the most contentious social issues debated in Annapolis in decades.

The New York effort was coordinated by the Human Rights Campaign, a national gay-rights advocacy group. The same organization is part of a coalition, known as Marylanders for Marriage Equality, pushing the issue in the Maryland, where a gay nuptials bill passed in the Senate last session but fell short in the House of Delegates.

Tessa Hill-Alston, president of the Baltimore chapter of the NAACP, which is part of the coalition supporting next year’s bill, said the Web campaign “will give state lawmakers the opportunity to see the depth and diversity of support for marriage equality.”

The names of others who will lend their voices to the effort are being closely guarded. One reasonable bet is Baltimore Ravens linebacker Brendon Ayanbadejo, who spoke out in a video during the previous debate.

Organizers insist the Web campaign is only loosely patterned on that of New York, where Gov. Andrew Cuomo (D) pushed a same-sex marriage bill through the legislature in June. About 50 of the 30-second videos were produced in the run-up to the votes there.

Although several politicians were highlighted along the way, the New York debut featured actress Julianne Moore.

The same swelling music that was used in the New York videos accompanies O’Malley’s plea, which builds on arguments he has made since announcing in July that he will sponsor the bill in Maryland next year.

“The legislation we plan to introduce in the 2012 legislative session will protect religious freedom and equality of marital rights under the law,” O’Malley says in a scene shot in his State House office. “I ask you to join us as we work to pass marriage equality in the state of Maryland.”

Many of the New York ads weren’t quite as straight-laced. Larry King, the long-time talk show host who has married eight times, poked fun at himself in one spot.

“I know a thing or two about marriage ... maybe three, maybe four,” King playfully told viewers. “Some of us can get married again and again, and others can’t get married at all. Can’t figure that out.”

In another ad, Ben Cohen and Jerry Greenfield, founders of Ben & Jerry’s ice cream, appeared together. “You know, marriage is like good ice cream,” Greenfield said. “It brings out the joy, no matter which flavor you love.”

The New York campaign — and others like it — are “really all about creating a narrative that resonates with the appropriate target audience,” said Lynn Greenky, a professor of communication and rhetorical studies at Syracuse University, where she teaches a course on public advocacy.

In that respect, the use of familiar Manhattan-based faces made sense in New York state, she said. The ads played up the vibrancy of New York City and appeared largely geared toward the constituents of several downstate lawmakers whose votes were in play.

The dynamic in Maryland is different, which is one reason organizers of the new Web campaign will have a different feel, with fewer celebrities and more everyday people.

Several lawmakers who balked at supporting the bill last session said they were concerned it did not contain sufficient accommodations for religious groups opposed to same-sex marriage. Opposition was particularly strong among black church leaders in Prince George’s County.

Accordingly, the Maryland ad campaign is expected to feature several clergy members and African American leaders from various walks of life, organizers say.

Whether it changes any votes remains to be seen.

“It certainly could be effective, but they also run the risk of motivating the opposition,” said Todd Eberly, a professor of political science and public policy at St. Mary’s College of Maryland, who has closely followed the debate in Annapolis. “What they have to be prepared for is it may actually cause a backlash.”

The first challenge might be getting the right people to pay attention. The audience for Web-based campaigns remains “pretty self-selecting,” Greenky said.

In New York, several of the ads generated enough buzz that they were covered by newspapers and television.

That happened, for example, when Barbara Bush, the daughter of the former president, made it known her position was different than that of her father. And when Sean Avery, a New York Rangers hockey star was featured, that became news in the sports pages.

Although there’s no guarantee such campaigns will succeed, they cater to the way research has shown people think about many public-policy issues, said Jeffrey Niederdeppe, a professor of communication at Cornell University.

“Having high-profile people voice a view can be helpful,” he said. “We’re hard-wired to make use of examples.”