The widow of the late Arizona Sen. John McCain, Cindy, praised her husband’s “unlikely friendship” with presumptive Democratic nominee Joe Biden during a video aired Tuesday at the Democratic National Convention. John McCain, a former Republican presidential nominee, was known for his willingness to work in a bipartisan manner with Democrats.

“They would just sit and joke,” Cindy McCain said in the prerecorded video for the DNC about the John McCain-Joe Biden relationship. “It was like a comedy show sometimes to watch the two of them."

"It was a friendship that shouldn't have worked. John, a former Navy pilot just released from a North Vietnamese prison. Joe, a young senator from Delaware," the narrator said in the video. "But in the 1970s, Joe was assigned a military aide for a trip overseas."

"I was a Navy Senate liaison and used to carry your bags on overseas trips," John McCain said in the video, referring to Biden.

"The son-of-a-gun never carried my bags. He was supposed to carry my bags there but he never carried my bags," Biden replied in another clip from a 2007 speech.

“My husband and Vice President Biden enjoyed a 30+ year friendship,” Cindy McCain said in a Twitter post. “So I was honored to accept the invitation from the Biden campaign to participate in a video celebrating their relationship.”

John McCain had a tense relationship with President Donald Trump. In 2015, Trump questioned whether the longtime senator was a war hero because he was captured during the Vietnam War. Trump had also called John McCain a “dummy.”

After John McCain died in 2018, his family invited Biden to speak at the funeral. Trump was not welcomed to attend.

Trump has not hid his animosity. In June 2019, the U.S. Navy acknowledged that a request was made to hide the USS John S. McCain vessel when Trump visited Japan in May of that year.