Donald Trump provided a video statement praising the work of his five predecessors
The five living former US presidents have made a rare joint appearance in Texas.
Jimmy Carter, George HW Bush, Bill Clinton, George W Bush and Barack Obama all took to the stage at the One America Appeal event - a fundraising concert for victims affected by recent hurricanes in the US & Caribbean.
Hurricanes Harvey, Irma and Maria led to widespread damage across areas including Texas, Florida, Puerto Rico and the US Virgin Islands.
The One America appeal effort has raised more than $31 million so far, organisers have said.
While Donald Trump was not in attendance, the current US president released a video statement for the event - praising his predecessors for their "tremendous assistance".
Speaking at the event, Mr Obama observed: "As former presidents, we wanted to help our fellow Americans begin to recover."
93-year-old Jimmy Carter highlighted the work of the Habitat for Humanity charity, saying: "Let's all work together, and make America still a greater volunteer nation."
George W Bush, meanwhile, said that they "admire and love" his 93-year-old father, who remained seated on stage.
Lady Gaga was another high-profile guest at the event, and tweeted a picture of herself with the former presidents:
The former presidents' joint appearance and Mr Trump's complimentary message proved to be a rare show of unity between the six men in a week that saw two of the former presidents appear to offer thinly-veiled criticisms of the current administration.
George W Bush did not name Trump directly in a high-profile speech on Thursday - but the remarks were strongly critical of the current state of the nation.
He suggested: "Bigotry seems emboldened. Our politics seems vulnerable to conspiracy theories and outright fabrications."
The speech was the most strongly worded intervention yet from the 43rd US president, and came on the same day his successor Barack Obama again hit out at Trump-era politics.
Obama argued: "Instead of our politics reflecting our values, we've got politics infecting our communities.
"Some of the politics we see now, we thought we put that to bed. It's the 21st century, not the 19th century. Come on!"