After having kept largely out of the spotlight during his father’s campaign, Hunter Biden delivered a rare address with his sister, Ashley, as a curtain-opener to Joe Biden accepting the Democratic Party’s nomination.

The pair focused their message at the convention largely on a tribute to their brother, Beau Biden, who died of brain cancer in 2015.

“Beau isn’t with us any longer, but he is still very much alive in our hearts, and we can still hear his strong voice just like it was yesterday,” the siblings said of their late brother.

A clip played of Beau introducing his father at a previous convention. “In moments both public and private he’s the father I’ve always known, the grandfather my children love and adore, my father, my hero Joe Biden,” Beau said.

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They also told of what kind of president their father would be: “He’ll be there when you need him,” said Hunter, and: “He’ll tell you the truth even when you don’t want to hear it,” Ashley continued.

Hunter said his father would be the strongest shoulder you’d ever lean on and would make your grandchildren feel like what they have to say matters.

“If you give him your cell phone number, he’s going to call it,” Ashley and Hunter Biden said.

Hunter Biden has been a favorite target of the president and his re-election campaign due to his past dealings in Ukraine and China. His personal life has also been a distraction for the Biden campaign, which has led to headlines over his reported history with drugs and a child support case resulting from an affair.

President Trump and his supporters have often repeated the slogan: “Where’s Hunter?” highlighting the son of the Democratic nominee’s notable absence throughout the President Trump's impeachment hearings and his father’s campaign.

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The Trump campaign plans to release a digital ad focusing on Hunter’s dealings with China while his father was vice president, suggesting he used his father's position for personal profit. Hunter Biden has denied wrongdoing.

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Part of the ad, which will run on YouTube, shows a reporter asking Hunter Biden if negotiations for a joint investment fund with a Chinese bank took place during a 2013 flight with the vice president for a Bejing trip they took together.