Melania Trump has hit back at Donald Trump’s first wife for referring to herself as “first lady”.

Ivana Trump told ABC’s Good Morning America on Monday that she talks to the president about every two weeks and has a direct number to the White House.

She added: “I don’t want to call him there because Melania is there and I don’t want to cause any kind of jealousy or something like that because I’m basically first Trump wife. I’m first lady, OK?”

Melania TrumpMelania Trump (Evan Vucci/AP)

Melania Trump’s spokeswoman, Stephanie Grisham, said there was “clearly no substance to this statement from an ex,” and called it “attention-seeking and self-serving noise”.

Ivana Trump is promoting her book, Raising Trump and Ms Grisham suggested she was trying to “sell books”.

Melania Trump, a native of Slovenia and former fashion model fluent in several languages, was rarely seen in the weeks after Mr Trump’s inauguration, and was usually at her husband’s side when she did appear in public.

Melania and Donald TrumpMelania is the most popular Trump in the White House, according to a CNN poll (Evan Vucci/AP)

In an unusual move for modern first ladies, she and Barron, the couple’s now-11-year-old son, lived at the family’s Trump Tower penthouse in New York for several months after the inauguration so he would not have to switch schools in the middle of the year.

They joined Mr Trump at the White House in June, and Barron started at a private school in Maryland.

She has more recently raised her profile, and talked about how she plans to “use my platform as first lady” to achieve her goals, including helping children suffering from cyberbullying.

Melania is the most popular Trump in the White House, according to a recent CNN survey in which 44% of those polled said they have a favourable opinion of the first lady.

She beat her husband, stepdaughter Ivanka Trump and Jared Kushner, Ivanka’s Trump’s husband, in the poll late last month.

It is usual for first ladies to be more popular than their husbands, who are called upon to sound off on a host of difficult issues, and Donald Trump, who has experienced some of the lowest public approval ratings of a first-year president, has called attention to his wife’s popularity.

Ivanka TrumpIvanka Trump is not as popular as Melania (Alex Brandon/AP)

“She’s become very, very popular, I’ll tell you that,” he said after she introduced him at a recent event at Joint Base Andrews in Maryland.

He said she has become an “incredible emissary” for the American people, and he was “very proud of her”.