Reports that first lady Melania Trump will join her husband at a closed-door, White House function later Tuesday (AEST) have done little to quell theories attempting to explain her 25-day absence from the public.

The White House schedule lists the Gold Star Families Memorial Day Reception as a closed-press event and says the first lady will be in attendance alongside President Donald Trump.

But breaking cover behind closed doors hasn’t stopped rampant speculation about Mrs Trump’s health and situation.

Shortly before it was reported she will attend the Gold Star function for families of soldiers killed in action, it was announced that Mrs Trump won’t be joining her husband for two high-profile overseas trips.

Despite it being a short flight away on Air Force One, she “will not attend” the G7 summit in Canada on Friday and Saturday, according to her communications director Stephanie Grisham.

Mrs Trump, 48, has also pulled the pin on accompanying the President for arguably his most important trip yet, his historic summit with North Korean leader Kim Jong-un in Singapore on June 12.

“There are no plans for her to travel to Singapore at this time,” Ms Grisham said of the first lady.

The surprise news comes after Mrs Trump failed to welcome reality TV star Kim Kardashian West to the Oval Office last week – a golden photo opportunity Mr Trump, 71, had to handle alone – and skipped a children’s sports day on the White House lawns.

But it’s not just public commitments Mrs Trump shunning.

She stayed behind at the White House last Friday when Mr Trump and his children Don Jr, Ivanka and Tiffany and son-in-law Jared Kushner headed to the Camp David retreat for the weekend.

Also apparently absent from the family getaway was Barron Trump, 12, her only child with Mr Trump.

According to celebrity website HollywoodLife, Mrs Trump’s friends outside the White House are “genuinely” starting to worry about her.

“Nobody has heard from Melania over these past few weeks, and her cell phone has been switched off,” said a source.

“To have radio silence for this long is just strange. Something is going on, but nobody knows what. It’s definitely concerning.”

Twitter has been alight with questions:

Where is @FLOTUS? And why was she in the hospital so long? Is she sick? Did she have a breakdown? Did @POTUS force her to get plastic surgery? Was the whole thing a scam? This is not a joke. These are legit Q’s abt America’s First Lady that remain unanswered. #Melania #Trump

— Andy Ostroy (@AndyOstroy) May 31, 2018

WHERE ARE WHITE HOUSE LEAKERS WHEN WE NEED THEM?????!!! Where is #Melania???? Has she divorced him? Did she have major plastic surgery? Is she with her boyfriend on a vacation?? Has anyone seen Baron?

— Rosemarie Pierce (@UhohitsRo) June 2, 2018

I can't believe they recast #Melania in the middle of the season. pic.twitter.com/i4nEgpj5vO

— Miss Sunshine ☀️ (@78_MissSunshine) June 4, 2018

Am I the only one who thinks this weekend at Camp David is a family meeting to discuss the announcement that #Melanie, aka #Melania, has quit the shitshow?

— Jean Mobilia (@jeanmobilia) June 2, 2018

Mrs Trump hasn’t been seen in public since May 10, when she and the President welcomed home three Americans released by North Korea.

Four days later, she was admitted to the Walter Reed Army Medical Centre for what the White House described as an “embolisation procedure” for a benign kidney issue.

Mrs Trump was reportedly expected to stay in the hospital for one night but ended up staying for five.

The President has been vague about his wife’s location and health, waving at an empty window last week at the White House when reporters asked about Mrs Trump.

In response to growing concerned buzz, a post to Mrs Trump’s Twitter account – its tone very similar to the signature social media style of the President – said she was “feeling great”.

I call upon any statement analysis experts who could (should) compare this tweet with previous Melania's previous tweets (although, of course, this would assume previous tweets were also written by Melania). Please retweet and share. #Melania #melaniamissing pic.twitter.com/ylUfzm9CW4

— DrJackBrown 🌊 (@DrGJackBrown) May 30, 2018

Earlier that day, Ms Grisham said the first lady had been working on projects including a picnic and having meetings with staff.

Conspiracy theories behind the Melania mystery have included that she is recovering from plastic surgery in private, that she’s fled to New York with Barron and that she’s holed up with special counsel Robert Mueller, co-operating with his Russia probe.

Another is that she’s in a secret location with Barack and Michelle Obama, dishing dirt for a tell-all project on her husband.

https://twitter.com/pacelattin/status/1000907279095353344

But a CNBC reporter tweeted this week: ‘Not that this will deter the conspiracy theorists, but I saw the First Lady walking with her aides in the West Wing yesterday afternoon.’