Kennedy will announce his support for Warren in a speech introducing her Saturday, they said.
It is not only Lawrence's connection to labor history that makes the city appealing for Warren to officially launch her campaign.
Warren's announcement comes a little more than one month after she announced an exploratory committee, the first step major candidates take when considering a run for president.
In the announcement, she called President Trump "the latest - and most extreme - symptom of what's gone wrong in America".
The campaign's decision to stage the senator's first campaign rally in Lawrence, a former industrial mill town, highlights the key constituency groups she hopes to appeal to in her campaign, including immigrants, women, working class families and union members. "This is the fight of our lives", she said, according to CNN. "It's time to fight back", Warren said.
Despite sub-zero temperatures and a blustery wind, an estimated crowd of several thousand turned out to hear the MA senator pledge to fight corruption in Washington, level the economic playing field and reform the USA democratic process. "I am in that fight all the way", she said.
Forbes lists Knicks net worth at $4B, NBA's most valuable franchise
He has been vocal recently about frustrations with the Knicks organization and the lack of playing time he has been receiving. The Houston Rockets were among the playoff teams who had interest in signing Matthews after his buyout, sources said.
Warren has too much baggage - all that "Pocahontas" nonsense - and she is too much like Hillary Clinton.
"We all want a country where everyone, not just the wealthy, can take care of their families ... where everyone can participate in democracy, where every child can dream big and reach for real opportunity ... to build an America that works for everyone".
The 69-year-old from the USA state of MA has already become a main target of Trump, who has dubbed Warren "Pocahontas" for previously identifying herself as a Native American, a controversy that has plagued the run-up to her candidacy.
Elizabeth Warren essentially has been disqualified from a presidential run by virtue of her claim, in 1986, to Native American race on her Texas bar registration card.
She has been forced to apologise for claiming on several occasions in her early political career that she was of Native American descent.
The Cherokee Nation criticized Warren's announcement a year ago, saying her use of a DNA test is "useless" for determining tribal citizenship and that using DNA analysis to determine connection to any tribal nation is "inappropriate and wrong". Kennedy was a student of Warren when she was a professor at Harvard University.
Following her re-election to the Senate in the 2018 midterm elections, Warren announced the creation of an exploratory committee for her campaign in the 2020 presidential election. Tribal activists, who were sharply critical over DNA test and earlier refusal to address the harm it might have done to their interests, have mostly welcomed her apologies. On that form, she listed herself as an "American Indian" in her handwriting - and even after she apologized, she's faced strong criticism for it.