Updated

All five living ex-presidents appeared together for the first time since 2013 at a Texas concert for hurricane relief Saturday night.

Jimmy Carter, George H.W. Bush, Bill Clinton, George W. Bush and Barack Obama appeared together on stage at the start of the concert at Texas A&M University in College Station. Carter, Clinton, George W. Bush and Obama later made brief remarks appealing for national unity to to help those affected by hurricanes Harvey, Irma, and Maria.

"The heart of America, without regard to race or religion or political party, is greater than our problems," said Clinton.

The charitable appeal backed by the ex-presidents has raised $31 million since it began on Sept. 7, said Jim McGrath, spokesman for George H.W. Bush.

Grammy award winner Lady Gaga made a surprise appearance at the concert that also featured country music band Alabama, Rock & Roll Hall of Famer 'Soul Man' Sam Moore, gospel legend Yolanda Adams and Texas musicians Lyle Lovett and Robert Earl Keen.

The current president, Donald Trump, recorded a video message for the concert praising his predecessors as "some of America's finest public servants."

"This wonderful effort reminds us that we truly are one nation under God, all unified by our values and devotion to one another," Trump said.

Texas A&M is home to the presidential library of the elder Bush. At 93, he has a form of Parkinson's disease and appeared in a wheelchair at the event. His wife Barbara and George W. Bush's wife Laura Bush were in the audience.

The last time the five were together was at the dedication of George W. Bush's presidential library in Dallas, while Obama was still in office.

There is precedent for former presidents joining forces for post-disaster fundraising. George H.W. Bush and Bill Clinton raised money together after the 2004 South Asia tsunami and Hurricane Katrina the next year. Clinton and George W. Bush combined to seek donations after Haiti's 2011 earthquake.

Hurricane Harvey slammed into Texas and Louisiana Gulf Coast as a Category 4 hurricane on Aug. 25, unleashing historic flooding in Houston and killing more than 80 people. Shortly thereafter, all five ex-presidents appeared in a commercial for a fundraising effort known as "One America Appeal." In it, George W. Bush says, "People are hurting down here." His father, George H.W. Bush, then replies, "We love you, Texas."

Hurricane Irma subsequently hit Florida and Hurricane Maria battered Puerto Rico, while both devastated the U.S. Virgin Islands.

A website accepting donations, OneAmericaAppeal.org, was created with 100 percent of proceeds pledged to hurricane relief.

The Associated Press contributed to this report.