Former President Bill Clinton took a break from the campaign trail Monday night to give a speech for a billionaire Democratic donor and friend of the Clinton Foundation.

The Fox Business Network reports:

A spokesman for the former president confirmed to FBN that Clinton is scheduled to speak Monday night at the Breakthroughs in Medicine & Technology Summit, which is designed to “have interactive conversations about breakthroughs in medicine and technology that will greatly impact humanity, industry and economy on a global basis,” according to the event website.

The conference, put on by billionaire surgeon and UCLA professor Patrick Soon-Shiong, featured Bill Clinton as a speaker during its first year in 2015. Soon-Shiong is chief executive at NantHealth, which has ties with The Clinton Foundation dating back to at least January 2014, when the two partnered on a computer system focused on patient access to healthcare information.

Soon-Shiong has spoken at conferences organized by The Clinton Foundation, as well.

Bill Clinton’s appearance at this year’s Breakthroughs conference in Jackson Hole, Wyoming is “raising eyebrows” in light of recent revelations about the Clinton Foundation securing very large speaking fees from groups doing business with the federal government while Hillary Clinton served as President Obama’s secretary of state, including large sums from foreign governments, and corporations like Morgan Stanley and Goldman Sachs, according to the news site.

Hillary Clinton has steadfastly refused to release transcripts of her speeches on Wall Street.

“Angel Urena, a spokesman for Bill Clinton, said neither the president nor the Clinton Foundation will receive honorariums for his speech this year,” FBN reports. “A spokeswoman for Soon-Shiong confirmed Bill Clinton’s attendance and said no speakers at the conference will receive speaking fees.”

The news site noted that Bill Clinton typically secures a speaking fee of at least $100,000.

“It’s a high probability that that he’s not getting paid and the reason is because it comes down to timing of the event” Democratic political consultant Hank Sheinkopf said. “He’s not going to take a risk.”

Soon-Shiong, who is worth an estimated $12 billion, is part owner of the Los Angeles Lakers and major shareholder of the former Tribune Company, now known as Tronc. He’s contributed regularly to Democratic candidates and the Democratic National Committee in recent elections, FBN reports.

Federal Election Commission records show Soon-Shiong and his wife Michelle donated money to the 2010 campaigns of Democratic U.S. Sens. Tom Harkin, of Iowa, and Harry Reid, of Nevada, as well as the 2009 campaign of Sen. Arlen Spector, of Pennsylvania.

The couple also sent about $60,800 to the Democratic National Committee in 2009, the same year daughter Nika Soon-Shiong – who was listed as a student – also donated $30,400 to the DNC.

Patrick Soon-Shiong also contributed $30,400 to the DNC in 2010, according to the FEC.

For 2016, he sent $60,000 in “soft money” to the Arizona Grassroots Action PAC.

The Soon-Shiong family has contributed a total of about $1.7 million on political candidates, the vast majority in the Democratic Party.