They weren't hiding anything. On May 6, President Trump's eldest son, Donald Trump Jr., attended a send-off party for his father's new ambassador to Germany — and Fox News host Kimberly Guilfoyle was by his side. After the bash, the pair, who reportedly had been secretly dating for weeks, were spotted at upscale restaurant Harry Cipriani, and within days, the news was public. "They seem very into each other," a source tells In Touch. "Everyone in Donald's circle is talking about them dating."

That includes his estranged wife, Vanessa. Less than two months after the model-turned-mother of Don Jr.'s five kids moved to end their 12-year marriage amid a cheating scandal — sources have previously told In Touch that Don Jr., 40, had an affair with reality TV star and pop singer Aubrey O'Day, 34, when they worked together on The Celebrity Apprentice in 2011 and 2012 — the businessman has moved on.

donald trump jr kimberly guilfoyle getty

"Kimberly and Don have known each other for a number of years, at least a decade, and Vanessa knows her, too," says the source, adding that Vanessa, 40, "isn't exactly thrilled over the relationship. She's been through so much public humiliation already with this divorce, which is only getting messier. She just wants to protect their kids, and she'll be even more embarrassed and pissed off at him for having another girlfriend already, especially now that the public knows."

His timing might be rotten, but people who know Don Jr. and Kimberly insist they're a great fit — "especially with his role in politics right now," says the source. Kimberly, 49, is a twice-divorced former prosecutor-turned-Court TV analyst who now hosts The Five on Fox News. She briefly modeled for Victoria's Secret in college and was even in the running to be the president's press secretary in 2017.

"Kim's been tight with the Trump family and has grown close to them," adds the source. "She's pretty, smart, ambitious, and knows how to work the circles that Don travels in. They've also both been through the ringer with marriages that have failed and both have kids. They have a lot in common."

donald trump jr.

It's not the first time Kimberly's been linked to a man in the midst of a divorce. In 2017, she was said to be dating "The Mooch" — former White House Communications Director Anthony Scaramucci, who at the time was in the middle of a bitter divorce with wife Deidre Ball (they've since reconciled) — after they were seen spending time together, including in Italy.

In 2005, she split from her first husband, then–San Francisco Mayor Gavin Newsom (now California's lieutenant governor), after three years of marriage. They blamed the split on her work in NYC and his in California, but in 2007 it emerged he'd allegedly had an affair with his re-election campaign manager's wife. Kimberly, who’s known for being outspoken — in 2004, she made headlines when she joked about her husband's penis size and her sexual abilities at a gay rights dinner — split from furniture heir Eric Villency, the father of her 11-year-old son, in 2009 after three years of marriage.

As for Vanessa, she wants to keep her and Don's split as civil as possible. But the source thinks things could turn very ugly, "especially if she feels like he's embarrassing her more" in the wake of the Aubrey O'Day scandal. "She's a good mother and would not want to turn her kids against him, but I do think she will fight for every cent she can get, especially when she knows how much that will hurt him."