A source who attended last night’s reception in Brooklyn with would-be AG Kathleen Rice said the borough’s powerful Democratic chairman, Vito Lopez, made no secret of the fact that the Nassau County DA is his preferred candidate.

According to his source, Lopez said the Brooklyn Dems will hold an endorsement vote in two weeks (on May 12). He predicted Rice will be the organization’s candidate, noting that somewhere between 4 and 4.5 percent of the committee’s weighted vote was present in the room at Eamonn Doran’s last night.

Brooklyn would be a significant feather in Rice’s cap, since it accounts for the second-highest percentage of the weighted convention vote – 9.14, to be exact; Manhattan is first with 10.03. She already has the support of her home county, Nassau (led by state Democratic Chairman Jay Jacobs), which is worth 7.83.

What’s more, according to my source, Lopez also suggested that the Queens Dems (8.44) would end up backing Rice, and confidently predicted the DA would surpass the 50 percent mark at the convention, making her the party’s official nominee for AG.

Lopez mentioned an informal vote taken by Democratic county chairs yesterday in Albany that found Rice to be the overwhelming favorite. I’m still trying to track down information on that one.

Adding additional intrigue to the primary, Lopez called Rice the preferred candidate of the presumptive Democratic gubernatorial nominee, AG Andrew Cuomo, my source said.

That has been widely speculated, since Cuomo is believed to be very interested in ticket balancing and Rice not only is the only woman in the field (unless Liz Holtzman formally enters the race), but also hails from the suburbs, which is going to be a battleground this fall – particularly if Suffolk County Executive Steve Levy ends up as the GOP candidate in the general election.

If Brooklyn goes with Rice, it will be a particular blow to Sen. Eric Schneiderman, who has been focused on playing a downstate game and wooing progressive/liberal voters as well as Latinos and African Americans.

(The downstate strategy makes sense, since between 50 and 60 percent of the primary vote tends to come from NYC, but the outer boroughs are believed to be up for grabs, since there all the city residents currently in the running – Schneiderman, Eric Dinallo, Sean Coffey – are Manhattanites).

Westchester Assemblyman Richard Brodsky also hails from the suburbs, of course. But he’s a white man, which doesn’t help the ticket-balancing effort much from a diversity standpoint.

For the record, Brodsky insisted last week during an interview with me on “Capital Tonight” that 1) Cuomo has informed him he won’t be endorsing anyone running for the job he’s expected to give up to run for governor, and 2) the whole ticket-balancing thing is IRrelevant in this year’s elections.

(NOTE: Yes, that’s IRRELEVANT, not relevant. My typo. Sorry).