Princess Ingrid Alexandra of Norway makes history with royal first as father King Haakon VIII is sworn in

Princess Ingrid Alexandra has broken tradition by joining her father, King Haakon VIII, in swearing the constitutional oath.

As per Hello! Magazine, this is a ‘historic first’ for the Norwegian Royal Family, as a future heiress has never taken the oath alongside the new monarch before.

On Tuesday (1 September), the new King, Haakon, 53, was sworn in during an official ceremony in Oslo parliament, following the death of his father, King Harald V, who died aged 89 on Friday (28 August), after he was taken to hospital last week to get treatment for a rare blood condition.

The monarch sat on a golden throne today as he read his oath, which, translated from Norwegian, reads: "I promise and swear to govern the Kingdom of Norway in accordance with its constitution and laws, so help me God the Almighty and the All-Knowing!"

“The Queen and I confirm that we are available to carry out our duty for the country and the people."

As reported by Town&Country, Ingrid will sign the oath herself later today.

Princess Ingrid Alexandra wore a long mourning dress as she accompanied her father, who swore the constitutional oath (Odd ANDERSEN / AFP via Getty Images)

Queen Mette-Marit, King Haakon’s wife, was not present during the ceremony, and the Royal House announced this was due to complications following her lung transplant in June.

This is why, instead, Crown Princess Ingrid, 22, accompanied her father for the important day, acting as first lady in her absence.

Standing alongside her father during the oath-swearing ceremony is the second time that Ingrid has made history in recent weeks.

Following her grandfather’s death and her father stepping up as King, she also became heir to the throne.

This breaks a 600-year-long tradition, as the last female monarch was Queen Margaret, who died in 1412.

Haakon has adopted the motto All for Norway, which dates back to his great-grandfather.

He was driven the short distance from the royal palace to the Storting, or parliament, in an open car, and there, speaker Masud Gharahkhani read the official announcement of Harald’s death and Haakon’s succession.

The new King read the oath from a golden throne (LISE ASERUD/Getty Images)

Gharahkhani also spoke of the new Queen's absence, as he said: “I know that our new queen really wanted to come. But she is in a rehabilitation phase and it is a family in mourning. Everything that happened yesterday, with following the bier to the Palace Chapel, is tough."

Meanwhile, pulmonologist Are Holm, Head of the Department of Respiratory Medicine at the National Hospital, said in a statement shared by the Norwegian palace: "It is not uncommon for complications to occur after a lung transplant.

"The Queen has had complications on some occasions since the operation, including today."

He added: "As a result, the Queen must be observed throughout the day. The Queen will therefore unfortunately not be able to attend the swearing-in ceremony in the Storting today.”