What was the Palm Beach socialite with ties to Donald Trump Jr. doing sitting behind him and his fiancée at the Republican National Convention?

She's the lady in red!

Page Six has learned that socialite Bettina Anderson was seated directly behind Donald Trump Jr. and his fiancée Kimberly Guilfoyle at the recent Republican National Convention.

The Daily Mail reported Last week, Don Jr. was spotted looking cozy with Anderson — and even “kissing” — during a recent brunch at Honor Bar in Palm Beach, and is “the talk of the town.”

The tabloid published more photos of Anderson and Don Jr. attending the same party in Jupiter, Florida, last month, which Guilfoyle reportedly did not attend.

Anderson, 37, can also be seen in photos, Page Six has learned, sitting behind Trump and Guilfoyle at the convention in Milwaukee, Wisconsin, in mid-July.

The stylish socialite attended the Republican event on Wednesday night and can be seen in photos applauding in a glamorous red outfit.

She was also photographed chatting with Don Jr.'s ex Vanessa Trump, 46, at the event, and we've learned the two are close friends. Sources said she attended with Vanessa.

In some shots, the duo sat next to each other, and also near the rest of the Trump family.

Anderson can also be seen in the background of an image posted by Don Jr. on Instagram of himself and Hulk Hogan at the convention.

A Republican insider told us the seat where Anderson was seen was “open” and “not an assigned seat.”

Back in Palm Beach, depending on who you talk to, Don Jr. and his fiancée of four years, Kimberly Guilfoyle, are either on the ropes — or stronger than ever — as the couple heads to appear Friday at a Texas young conservatives conference.

Trump allies say the photos of the lunch with Anderson were exaggerated and just part of a campaign to smear Don Jr., 46.

Both parties also note that Anderson is close friends with Don Jr.'s ex, Vanessa.

“Don and Kimberly have not been getting along for the past year,” a source tells Page Six. “They get into arguments at Mar-a-Lago in front of people. Nothing crazy, but you know when a couple is fighting. They fight in public.”

But a number of Trump insiders insisted to Page Six on Thursday that all is well between Trump and Guilfoyle.

“They are 100 percent together. They love each other,” a source said. Another Trump family friend also tells us the couple is “closer than ever.”

We learn that the couple is still living together, will continue to campaign together and will also embark on a trip to Europe.

Following the Daily Mail report, Guilfoyle posted photos showing the couple at an event called Patriot's Day Freedom Fest, where she was giving him a kiss on the cheek.

Anderson, meanwhile, posted an image on her Instagram account that read: “Gossip is the devil’s phone. Best to hang up. -Moira Rose” (making a cheeky reference to an exaggerated character from the show “Schitt’s Creek”).

She posed in front of a sign that said “Private,” just in case.

He later posted a clip from “Meet Joe Black” in which Anthony Hopkins opines: “Love is passion. Obsession… Find someone you can love madly.”

The socialite also previously posted a melancholic black and white photograph with the caption: “She was not afraid of the flame, she became the fire.”

Anderson is by no means a big MAGA donor. Her only donation to the GOP appears to have been in 2022, when she gave $2,800 to Florida Republican Maria Salazar.

Guilfoyle was Reportedly “taken by surprise” for the news Don Jr. was dating Anderson.

Anderson, whose father was banker Harry Loy Anderson Jr. and whose mother, Inger, was a favorite of famed photographer Slim Aarons, began posting pro-Donald Trump content on her Instagram feed over the past month, according to a source.

A source told us about Guilfoyle's relationship with the Trumps: “The family doesn't like it.”

But another insists that this is not true. “I have heard the president talk about Kim privately many times, and it has always been positive,” we were told. “This all seems exaggerated.”

In December 2022, Page Six had heard the same rumors: “The feeling is that the family doesn’t like Kim. She’s trying too hard to be in the family.”

However, Eric Trump told us when we reached out for comment: “I completely disagree with that narrative and I think Kimberly is wonderful.”

The couple began dating in 2018 and got engaged in 2020. Guilfoyle was previously married to California politician Gavin Newsome and design executive Eric Villency.

This week, the Palm Beach Daily News (locally nicknamed “the Shiny Sheet”) wrote in its print edition that its spies also detected Anderson and Trump Jr. (although the online version leaves that as a hidden article).

“The couple recently put on a poolside PDA show at a local club that convinced all onlookers that A) Kimberly is history; and B) someone is getting a no-PDA letter from the club,” the article reads.

A local source tells us he may have been referring to the Beach Club or Breakers, as other clubs with poolside dining are still closed for the season. (Honor Bar does not have a pool.)

Representatives did not respond to requests for comment.