Former President Barack Obama made a surprise appearance at the White House state dinner Thursday for Kenyan President William Ruto and First Lady Rachel Ruto.

While the 44th President of the United States was not listed on the initial guest list at the dinner hosted by President Joe Biden and First Lady Dr. Jill Biden, Obama briefly turned up following a reception earlier in the Blue Room, CNN, The New York Times, and USA TODAY reported.

"There is a bright light at the White House tonight," Biden said to Ruto during his toast that evening, according to CNN. "Jill and I are honored to have you here."

He joked that "many members of the African diaspora," including Obama – whose father is Kenyan – had "just left," CNN reported. On a more serious note, he said Obama was "very gracious" to meet with Ruto earlier in the day.

"We share a strong respect for the history that connects us together," Biden said during his toast to the Kenyan president, according to USA TODAY. "Neighbors do not share a border but share beliefs," he added, quoting former President Jimmy Carter.

Ruto reciprocated the sentiment and wished the Bidens "continued wellbeing and long life."

Among the 500 attendees at the star-studded event were former President Bill Clinton, former Secretary of State Hillary Clinton, philanthropist Melinda French Gates, actors Sean Penn and LeVar Burton, and country star Brad Paisley, the Times reported.

Sen. Ralph Warnock (D-GA) and Sen. Chris Coons (D-DE) were also in attendance.

Guests dined on chilled heirloom tomato soup, fruitwood-smoked beef short ribs, and butter poached-lobster, USA TODAY reported.