Gov. Gavin Newsom is scheduled to appear in the first vice presidential debate with former President Trump in Philadelphia on Tuesday, but before that he'll head east to headline a glitzy, big-budget fundraiser for Democratic presidential candidate Kamala Harris in New York.

According to members of Newsom's political team, the governor plans to promote Harris and his running mate, Minnesota Gov. Tim Walz, from Sunday through Wednesday, make media appearances and fundraisers in New York and campaign for the Democratic candidate in the battleground state of Pennsylvania.

Newsom, who kept a largely low profile in the weeks since Harris supplanted Biden as the top candidate, is jumping back into the Democratic campaign fray. As a prominent Biden surrogate, Newsom campaigned for him across the country and defended him after Biden's poor performance in a June debate and the incumbent's eventual withdrawal from the reelection campaign.

But Newsom's role in the Harris campaign was unclear. A Harris campaign official said Saturday that Newsom will lead the Harris campaign's national campaign committee, the same role he held for the Biden campaign.

Harris and Newsom have a long history together, having been active in the same political circles in San Francisco in 2004, with Newsom being sworn in as mayor and Harris as district attorney on the same day.

The vice president reminisced about the pair's friendship at his first Bay Area fundraiser since clinching the Democratic presidential nomination in August.

“I've known Gavin as a friend and colleague for many years,” she said. “In front of all of our friends here, I want to thank you for being an extraordinary leader for California and the country.”

Still, there has been something of a rivalry between the two men over the years, as they were both seen as rising stars in the Democratic Party, and this was especially evident at last month's Democratic National Convention, where Newsom attended but did not take a prominent role.

The governor, who normally shuns the spotlight, only appeared in front of the cameras briefly during the official program to announce that California's delegates had voted for Harris. The governor said he turned down the opportunity to speak on the first day of the convention because he was attending his children's school orientation and would not have made it to Chicago in time.

In an interview during the convention, Newsom said he was waiting for guidance from the Harris campaign and was mindful of how the rest of the country views San Francisco and California.

“I am very aware of the situation and that is why I do not claim anything,” he said. “I am happy. I don't need anything, I don't want anything. I just want to be helpful, not hurt.”

One way Newsom is helping is through fundraising. Invitations for a fundraiser in New York City on Sunday ask donors to give up to $100,000 to attend an event headlined by Newsom, former House Speaker Nancy Pelosi of San Francisco and House Minority Leader Hakeem Jeffries of New York. Hosts include producer Shonda Rhimes and actors Tony Goldwyn, Robert De Niro, Leslie Lloyd Odom Jr. and Amber Tamblyn.

The fundraising comes as campaign disclosures reveal that Harris has a large financial lead over Trump. The Democratic candidate's campaign said Friday that Harris, Walz and an alliance committee raised $361 million in August, the highest total so far this election cycle, and have $404 million in cash on hand.

According to the GOP, Mr. Trump, his running mate J.D. Vance and their allied committees raised $130 million in August and have $295 million in the bank. The former Republican president is scheduled to return to California this week to attend two big-ticket fundraisers, one of which will be hosted by a relative of Mr. Newsom's wife, according to invitations obtained by The Times.

Newsom is scheduled to visit Pennsylvania after New York. Harris will debate Trump on Tuesday at the National Constitution Center in Philadelphia. Her aides referred questions about attending the debate to her campaign, which did not respond to questions from The New York Times.

A source familiar with the planning, who was not authorized to speak publicly, said Newsom is widely “expected” to enter the showdown as a vocal surrogate for Harris in her historic fight against Trump.