Graduating seniors across the United States who are missing traditional commencement events because of the coronavirus pandemic have had stars step up to fill the void. Last month, Oprah Winfrey announced that she would address seniors; the very next day, LeBron James said he was organizing a prime-time special for graduates. Now, former President Barack Obama has announced that he too will celebrate graduating seniors in at least three events.

On May 16, Mr. Obama will participate in “Show Me Your Walk, HBCU Edition,” an event for historically black colleges and universities, he announced on Twitter on Tuesday. Later that evening, he is scheduled to deliver the main address at “Graduate Together: High School Class of 2020 Commencement,” a virtual event organized by Mr. James’s foundation.

The former president will give another address in a YouTube event titled “Dear Class of 2020,” along with Michelle Obama, the K-pop group BTS, Lady Gaga, former Secretary of Defense Robert M. Gates and others on June 6. Alicia Keys, Chloe x Halle and Kelly Rowland will also make appearances.

“I’ve always loved joining commencements — the culmination of years of hard work and sacrifice,” Mr. Obama said on Twitter. “Even if we can’t get together in person this year, Michelle and I are excited to celebrate the nationwide Class of 2020 and recognize this milestone with you and your loved ones.”

“Whether you’re graduating from high school, college, or any other kind of school — we want you, your family, and all of your loved ones to be a part of this celebration,” Mrs. Obama said on Twitter.

While it was not immediately clear how Mr. Obama ultimately got involved in the graduation events, a social media campaign started by a high school senior in Southern California has been trying for weeks to recruit him to give a national commencement address.

“Like most high school/college seniors, I’m saddened by the loss of milestone events, prom & graduation,” the student, Lincoln Debenham, 17, of Eagle Rock High School, said in an April 14 post that has been retweeted over 46,000 times. “In an unprecedented time, it would give us great comfort to hear your voice. We ask you to consider giving a national commencement speech to the class of 2020.”

“What inspired me to send my tweet was seeing President Obama’s endorsement of Vice President Biden for president,” Mr. Debenham said on Tuesday. “It reminded me all day what a great speaker he always was and how his words shaped my generation in many ways. I figured, Who better than him?”

Mr. Debenham said that while he hadn’t personally heard from Mr. Obama, he was planning to potentially watch all three of his appearances.

“It’s wild!” said Mr. Debenham, who plans to attend California State University, Los Angeles, in the fall to study political science. “I did expect him to do it regardless of whether I did that tweet or not. I’m still extremely excited about it.”