WATCH: Maryland Marriage Ad Features Presidents Obama and Clinton

Marylanders for Marriage Equality, the coalition working to pass the measure known as Question 6, released its final TV ad Friday featuring Presidents Barack Obama and Bill Clinton with the message that "it's time" for same-sex couples to be able to legally marry in the state.

The ad running in the Baltimore and D.C. markets says, "While there are those trying to divide us, Presidents Obama and Clinton stand with us," according to the script. Obama endorsed the campaign in Maryland last week, while the former president has spoken for marriage equality in New York and against the constitutional amendment that passed this year in North Carolina.

"Maryland ... it's time," says the ad. "Time for marriage equality."

"It's time" is the title of the marriage equality video from Australia that went viral and received millions of views last year. Since then, leaders including Washington governor Christine Gregoire have invoked the phrase to explain how they arrived at their decision to support marriage equality.

Question 6 includes protections for religious freedom, which are also mentioned in the TV ad and in a new newspaper ad featuring Julian Bond, the chairman emeritus of the NAACP. The NAACP National Voter Fund for Question 6 took out the full-page ad in the Afro newspaper.

"We deeply respect differences of personal conscience on the religious meaning of marriage," says Bond in the ad. "Question 6 strongly affirms the freedom of churches to celebrate marriages according to their tradition and conscience. But civil marriage licenses, like all civil rights provided by the government, must be provided equally to all Americans."

The campaign in Maryland makes African-American voters the focus of a marriage equality referendum for the first time. Black voters comprise about 25% of the voting population in the heavily Democratic state and are expected to turn out in large numbers to support President Obama.

Marriage equality opponents led by the National Organization for Marriage have tried to reach African-Americans in their own ads, and a Baltimore Sun poll over the weekend showing increased opposition from blacks toward Question 6 suggested the strategy might be working. Gov. Martin O'Malley dismissed the poll as an "outlier" and said he believes the campaign has a "real shot" at winning this Tuesday.