President Barack Obama's May endorsement of gay marriage will be featured in a TV ad, a gay rights group has said.

The Los Angeles-based group LegalizeLove.com on Monday called on Obama to record an ad in support of referendums taking place in four states, the AP reported.

Maine's first-in-the-nation initiative seeks to legalize gay nuptials. Referendums in Washington state and Maryland ask voters to uphold – or reject – marriage equality laws approved by lawmakers. And voters in Minnesota will decide on a constitutional amendment which would limit marriage to heterosexual couples.

The group says it plans to air a one-minute television ad in those states featuring Obama's declaration in support of such unions.

Their plan to recruit Obama included delivering a wedding cake with two grooms to Obama's campaign offices in Portland, Maine on Monday.

Eduardo Cisneros and his partner Luke Montgomery are also traveling the country in a “Legalize Love Bug,” a Volkswagen Beetle covered with “legalize love” bumper stickers.

“Because of a tight national race, we understand the president might not be able to hammer home his support for gay marriage himself, so we are stepping in to make sure that this new TV spot using his own words gets that message out no matter what,” Cisneros said in a statement.

Legalize Love also edited a one-and-a-half-minute video which includes many of Obama's most LGBT-supportive quotes. (The video is embedded on this page. Visit our video library for more videos.)