Lou Rocco/Disney General Entertainment Content via Getty; Samuel Corum/Getty Ana Navarro (left), Donald Trump Jr.
The results were later confirmed to be false positives.
At the time, Navarro and Hostin, 52, were informed of their results, they were preparing to bring Vice President Kamala Harris on stage for an interview.
Hours after Navarro received her false positive, Don Jr. tweeted: "Given the Ana Navarro news, I think it's time for a national conversation about the dangers of Covid-19 & obesity."
Navarro, a conservative commentator, has been outspoken about her criticism of the Trump family.
She discussed Don Jr.'s remarks on Monday's show, suggesting it was hypocritical of the president's son to criticize her considering is also overweight. (President Trump's last physical while in the White House showed him at 244 lbs. and 6-foot-3-inches.)
"Apparently, he thought it was appropriate to take advantage of the false news that I had COVID to take a shot at my weight," Navarro said on Monday. "Babe, I take a shot at my weight every day, okay? Unlike you, I have a mirror, and I know I have a weight issue."
She continued, slamming Don Jr.'s own career: "First of all, I mean, I know that when you are a dimwit, with no skill, or talent or significant accomplishments, living off your father's fame and name and fortune. You've got to draw attention to yourself. But baby if you want to have a conversation about COVID and obesity, you could have had it last October, when your elderly obese father had it."
In addition to nominally helping run the Trump Organization, Don Jr. has become one of his father's most prominent political surrogates, with a similar provocative style on social media and cable TV.
On Monday's The View, Navarro said that the link between COVID-19 and obesity is a "legitimate conversation to have" — suggesting that perhaps Don. Jr should have the conversation with his father rather than tweeting about her weight.
"Fortunately for you, you've got somebody in your family who you can call and discuss it with," Navarro said. "Because imagine having a father whose butt is the size of a studio apartment in New Jersey. You got the gall to pick on me about my weight?"
Fellow panelist Joy Behar, no fan of the Trumps, concurred with Navarro. Behar said that those with "nothing to say" are the ones who stoop to attacking others for their looks.
"He's such a loser, say God forbid, it's pathetic, Donald Jr. is the biggest loser in this country besides his father and his family," she said.
"At least I'm not orange or twice impeached," Navarro added.
"And never elected again," Behar said.
Navarro recently spoke to CNN about the chaos of Friday's episode, likening it to "an episode of Curb Your Enthusiasm."
She has in recent years been vocal about her feelings for the Trump family.
During a 2019 episode of The View, she joked that she needed to "disinfect" where she was sitting because it was the same spot where Don Jr. had sat the previous day for a contentious joint interview with his girlfriend, Kimberly Guilfoyle.