Long live the queen! Maria of Denmark is elegant in an all-white ensemble as she shares a kiss with her husband on the balcony of Christiansborg Castle

Mary of Denmark was elegant in an all-white ensemble as she appeared on the balcony of Christiansborg Castle today to formally become queen.

The abdication of Queen Margrethe II is in full swing and Australian-born Mary and her husband Crown Prince Frederik have succeeded to the throne of Denmark.

Margrethe, who has held the title of queen for 52 years, confirmed her intention to step aside for her eldest son on New Year's Eve, much to the surprise of the country.

Thousands of people gathered outside Christiansborg Castle on Sunday, prepared with folding chairs and waving Danish flags in the hope of catching a glimpse of the royals.

Mary and Frederik traveled together in a 1958 Rolls-Royce from Amalienborg, followed by Queen Margrethe in a carriage, leaving Christian IX's palace.

The king and queen were later seen with their four children on the balcony of Christiansborg Castle, where they shared a sweet kiss in front of the excited crowd.

The long-awaited balcony moment took place shortly after the Council of State was held at 2 p.m.

This involved Margrethe, Frederik and his son Prince Christian, but also representatives of the government and the State Secretary.

It marked the formal succession to the throne, and the moment when Her Majesty the Queen signed a declaration of her abdication – and Frederick and Mary became King and Queen.

Maria was a vision in white as she joined her husband on the balcony shortly after he was proclaimed King of Denmark by Danish Prime Minister Mette Frederiksen.

Her white silk dress (meaning new and innocence) had a glittering sash around her waist, which she paired with a brooch and a pair of pink, luscious earrings.

For the occasion, she swept her hair back, secured with a jeweled clip.

Meanwhile, her husband, Crown Prince Frederik, wore traditional military clothing, adorned with numerous medals, gold thread and a light blue sash.

They were accompanied by their four children: Christian, Isabella, Vincent and Josephine.

On the balcony of Christianborg Palace, the Danish Prime Minister formally declared the king's accession to the throne – and he became King Frederick X.

He then gives a short and tearful speech, rallying the hundreds below.

This will be followed by an honorary cannon salute from the Sixtus Battery – a heritage site in Holmen, Copenhagen – and the Royal Standard will then be lowered at the Palace of Christian IX (Margrethe's house) and raised again at the Palace of Frederick VIII, where the new king and queen are stationed.

Soon, Frederik and Mary will take a carriage from Christiansborg Palace back to Amalienborg, which will be escorted by a mounted squadron. Margrethe has already left.

The last moment of the day is at 5:00 PM, when there will be a transfer of the royal colors from the Palace of Christian IX to the Palace of Frederick VIII.

It comes as Mary has been labeled as the real 'power behind the throne' with people in the country already calling her 'King Mary', according to a royal author.

Trine Villemann also told Hello! that the Australian mother of four, 51, is a “much better communicator and public speaker” than her husband, Crown Prince Frederik.

Before Margrethe's daughter-in-law became queen, Danish royal author Trine said: 'Mary is truly the power behind the throne and will remain so for decades to come – there is no doubt about that.

'Frederik is a nice guy and he is very popular, but Mary is a much better communicator and public speaker. She has great skills and enormous talent, and people in Denmark call her 'King Mary'.

'Her approval ratings are also higher than the rest of the royal family… As we say in Denmark: long live King Mary!'

Denmark's new king and queen, who take up their roles this weekend, enjoy the support of more than 80 percent of the Danish population, a recent poll showed.

A study conducted for Ritzau revealed that Princess Mary enjoyed slightly more popularity among Danes than Crown Prince Frederik, as the royal family prepares to take the throne on January 14.

The poll asked to what extent Crown Princess Mary and Crown Prince Frederik are suitable to become Queen Mary I and King Frederik X, prior to the abdication of Queen Margrethe.

While 82 percent of people believe Frederick is suitable for the role of king, 86 percent believe Mary will make a good queen.

Danish royal commentator Kim Bach believes that while Frederik is popular, Mary's slight edge over her husband is likely due to rumors of an affair that circulated after the soon-to-be king was spotted on a night out with a Mexican socialite in Madrid.

Genoveva Casanova was forced to deny what she called “malicious” rumors after photos emerged of herself with the crown prince in the Spanish capital, where Spanish magazine Lecturas reported they had dinner together and watched flamenco dancing until 1am.

Mary has remained tight-lipped about her husband's dinner with the socialite, and the royal couple have made a number of public appearances together.

However, there is increasing speculation that Queen Margrethe's decision to abdicate may have been an attempt to keep Frederik's wife of 19 years aside.