About 1,500 students in the University of Pennsylvania's School of Arts and Sciences will collect their diplomas at a ceremony on May 15, but not all eyes will be on them.

Both Donald Trump and Joe Biden will be in the audience - not as presidential candidate and sitting vice president, but as parent and grandparent of two graduates: Trump's 22-year-old daughter, Tiffany (with former wife Marla Maples), and Biden's granddaughter Naomi.

Security will be especially tight, and Penn will be advising parents and students to get there early. Penn's police department is working with the Secret Service and city police to prepare for the event, including the possibility of protesters.

The ceremony is scheduled to begin at 6:30 p.m. at Franklin Field. (If there's a major weather threat, the event will be moved to the Palestra.)

Neither Donald Trump nor Vice President Biden is expected to be at the main commencement ceremony for all Penn graduates the following Monday, said Maureen S. Rush, Penn's vice president for public safety. That event also will be at Franklin Field. The composer and actor Lin-Manuel Miranda, whose Broadway musical, Hamilton, recently won the Pulitzer Prize for drama, is scheduled to address graduates.

Penn spokesman Stephen MacCarthy noted that Trump and Biden are not speaking at the May 15 ceremony.

"They're here as parents," said MacCarthy, vice president for university communications. "The focus is on the graduates. It's to celebrate their achievement. That's where we want the focus to be."

Penn has had its share of protected dignitaries visit over the years and has worked with the Secret Service before.

"All these relationships are well-built," Rush said.

But Rush said this is the first time in her 22 years overseeing Penn safety that she can remember having two protected individuals attend the same event, especially two with such current high profiles.

"This is probably the most unusual we've had so far," she said.

This won't be the first time Trump has been at a Penn commencement. His son Donald Jr. and daughter Ivanka both graduated from the Wharton School. (Trump himself earned a degree from the business school.)

Rush said Penn would not infringe on protesters' freedom of speech, but also will make sure any protest is orderly and does not detract from the ceremony or inconvenience graduates and their parents.

"We need to ensure all the people coming to see their kids graduate aren't inconvenienced," she said. "We will make sure this is seamless and everyone's safe."