(CNN) - Former President Bill Clinton will attend a fundraiser for a congresswoman from New York City who's challenging Sen. Kirsten Gillibrand in next year's Democratic primary.
The fundraiser is for Rep. Carolyn Maloney. Her campaign's chief strategist, Joe Trippi, tells CNN that Maloney has made her decision to run against Gillibrand and will soon formally announce her Senate bid.
Gillibrand, a former congresswoman from upstate New York, was named by Gov. David Paterson in January to succeed Hillary Clinton.
The White House has been hoping to prevent a primary fight next year in New York by trying to clear the field for Gillibrand. Steve Israel, another congressman from New York who was considering a run against Gillibrand, decided against such a bid after lobbying by the White House.
Former President Clinton has not made an endorsement in the race, but his appearance at a Maloney fundraiser will raise some eyebrows. Clinton also attended a fundraiser for Gillibrand earlier this year.
Last year, both Gillibrand and Maloney backed Senator Hillary Clinton in her run against Senator Barack Obama for the Democratic presidential nomination. The former president has made a point of thanking former Hillary Clinton supporters.
A spokesman for the former president, in reports today, confirmed that Clinton would attend the fundraiser on July 20, but said Clinton agreed to the Maloney event well before the congresswoman decided to challenge Gillibrand.
A Quinnipiac University survey released Wednesday indicates Gillibrand trails Maloney in a hypothetical Democratic primary matchup, with 27 percent of those questioned supporting Maloney and 23 percent backing Gillibrand. Forty-four percent are undecided.