The Kennedy family will endorse President Joe Biden over RFK Jr. at a Philadelphia campaign event

President Joe Biden will be endorsed by members of the Kennedy family during his visit to Philadelphia Thursday, a prominent showing of support from the relatives of one of his likely opponents, that wraps a three-day Pennsylvania swing aimed at reassembling a coalition, seven months ahead of the general election.

The event, at a recreation center in North Philadelphia this afternoon, will feature 15 members of the Kennedy family endorsing Biden over one of their relatives Robert F. Kennedy Jr., who is running for president as an Independent.

Kerry Kennedy, the sister of the presidential contender, daughter of former Attorney General Robert F. Kennedy, and niece of former President John F. Kennedy, will deliver the endorsements, Biden’s campaign announced.

“I can only imagine how Donald Trump’s outrageous lies and behavior would have horrified my father, Robert F. Kennedy, who proudly served as Attorney General of the United States, and honored his pledge to uphold the law and protect the country,” Kerry Kennedy will say, according to prepared remarks. “Daddy stood for equal justice, human rights, and freedom from want and fear. Just as President Biden does today.”

Rory Kennedy, RFK’s daughter, and Joe Kennedy III, RFK’s grandson will also appear at the endorsement event along with about a dozen other members of the Kennedy family.

The Kennedys had signaled their support for Biden before the official endorsement, with a photograph at the White House on St. Patrick’s Day and in comments members of the family had made about the campaign.

Kennedy Jr.’s candidacy has increasingly become a concern for Biden who fears he could siphon votes away and help Trump.

But the event, in Philadelphia, aims to further boost Biden who spent three straight days campaigning here, first in Scranton, then in Pittsburgh, as former president Donald Trump spent the week at his criminal trial in Manhattan.

Following the endorsement event, Biden and members of the Kennedy family will join campaign volunteers and supporters by making calls and knocking doors.

Kennedy has consistently polled between 7% and 9% in Pennsylvania, a margin that could impact the winner in a state where Biden and Trump have been neck and neck. In the most recent Franklin & Marshall survey of the state, Biden received support from 42% of respondents, Trump 40%, Kennedy 9% and Green Party candidate Jill Stein 3%.

The Democratic National Committee has hired a communications team to combat the appeal of third-party candidates, Kennedy first among them. The DNC also filed a recent Federal Election Commission complaint against Kennedy’s campaign, charging that it coordinated too closely with an affiliated Super PAC to get his name on the presidential ballot in Arizona, Illinois, and Michigan.

Kennedy is also viewed warily by the Trump campaign, which is fearful that he could also pull the GOP voters they need to defeat Biden in November. While Trump has released a recent video saying, “If I were a Democrat, I’d vote for RFK Jr. every single time over Biden,” he has also sometimes criticized Kennedy, including suggesting that he is more “radical left” than the incumbent president.

The Kennedys will be joined at the event by John White Jr., a former Pennsylvania state representative, and longtime civil rights leader, who will speak about the Kennedy family’s impact on his work in public service and President Biden’s leadership on civil rights, according to the campaign.

Biden has long cited the Kennedy family as influential in his decision to go into public service. He has a bust of Robert F. Kennedy in the Oval Office and often describes RFK. as one of his political heroes.

The Associated Press contributed to this article.