After WMUR and the Boston Globe reported on the endorsement, Kuster took to Twitter.

US Representative Annie Kuster of New Hampshire endorsed former mayor Pete Buttigieg’s presidential campaign on Wednesday, becoming the first member of the state’s four-person, all-Democratic Congressional delegation to formally back a White House hopeful. Kuster will hold a campaign rally with him in New Hampshire on Friday, less than a month before the Feb. 11 first-in-the-nation primary.

“With our country so consumed by division, @PeteButtigieg is the leader who can finally turn the page on the Trump presidency and bring our nation together,” she wrote. “He has the courage to break from the past to lead us to a better future—I’m excited to endorse him to be our next president.”


Kuster and Buttigieg is scheduled for 10 a.m. at the Grappone Center in Concord, the state capital.

There were signs that Kuster had been more interested in Buttigieg than in others. Early on, she saw her role as helping presidential candidates meet voters and hosted a number of events. But she hosted two gatherings for Buttigieg within weeks of each other in the late fall.

Then, on Friday night, she and her husband attended a dinner at a home in Concord with Buttigieg’s national policy director.

The host, Stonyfield Yogurt founder Gary Hirshberg, is one of Kuster’s close friends and the biggest Democratic donor in the state. Hirshberg endorsed Buttigieg last year.

In an interview Wednesday, Hirshberg said Kuster’s decision to endorse Buttigieg was “courageous.”

And if Buttigieg ends up winning the nomination, it won’t be the first time Kuster picked the eventual victor.

In 2008, when she was an adoption attorney and State House lobbyist, Kuster was among the first in New Hampshire to endorse Barack Obama’s campaign.

James Pindell can be reached at james.pindell@globe.com. Follow him on Twitter @jamespindell or subscribe to his Ground Game newsletter on politics:http://pages.email.bostonglobe.com/GroundGameSignUp