Barack Obama surprised more than 600 people attending a fundraiser at the Wilmington Country Club Monday.

An audible gasp was heard when the former president, along with former Vice President Joe Biden, were introduced to the audience attending the cocktail reception and silent auction to raise money for the Beau Biden Foundation for the Protection of Children.

"If I'd known that you were giving away a car on the hole-in-one, I would have played," Obama joked. On a more serious note, Obama said he was there to lend his voice and support to a family that he cares deeply about. And "to honor a man that I thought the world of and to say thank you to all of you for supporting this wonderful cause."

The annual Beau Biden Foundation Cocktail Reception and Silent Auction is a big fundraising event for the foundation, which works to expand and continue work training adults in child abuse prevention and kids and families in bully prevention.

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Monday's event raised more than $400,000. The foundation has raised more than $1.1 million in the last three events.

"Tonight's event helped shine a light on child sexual abuse," said Patty Dailey Lewis, executive director of the Beau Biden Foundation. "We heard from Vice President Joe Biden and President Barack Obama about the important work the Beau Biden Foundation does to ensure Beau's vision of a world free from child abuse becomes a reality."

Joe and Jill Biden, who stood next to Obama as he spoke to the audience, chaired the fundraising event.

Many took to social media, posting photos and videos, including Joe Biden, whose Twitter account showed a short clip of himself and Obama speaking.

Angela Taylor Holodick, who posted a picture and video of Obama speaking on her Facebook account, said it was exciting and calming to see the former president speak.

"This may be too political, but seeing and listening to the former president was inspirational," she told The News Journal. "It renewed my hope that amid the divisiveness spreading throughout our country today there are still many people working to improve our nation and world in an intelligent, mature and truly human way."

The Beau Biden Foundation was created in 2015 by Beau Biden's widow, Hallie, and the Delaware Community Foundation to continue work that Biden pursued while he was Delaware's attorney general. Biden, who died of brain cancer in 2015, made prosecution of child sexual abuse a cornerstone of his two terms.

Contact Esteban Parra at (302) 324-2299, eparra@delawareonline.com or Twitter @eparra3.