Major development in Princess Charlene's mystery health battle

Princess Charlene of Monaco has finally returned home. Photo / Getty Images

Princess Charlene has finally returned home to Monaco following her unknown illness and lengthy absence from public life.

After almost a year plagued by ill-health and mystery, the 44-year-old Monaco royal has reunited with her husband, Prince Albert, and their two children, Prince Jacques and Princess Gabriella, according to an official statement from the palace.

"As a result of Princess Charlene's encouraging recovery and her doctors' approval, their Serene Highnesses are delighted to announce that the Princess will now continue her convalescence in the principality, with her husband and children by her side," the statement read.

"Consequently Princess Charlene has already returned to Monaco where she has been happily reunited with her family and loved ones. The next few weeks should allow for Princess Charlene to further strengthen her health before gradually resuming her official duties and commitments."

The palace continued by saying Charlene "looks forward" to one day spending time with the people of Monaco, but needed more time to recover.

"In order for Princess Charlene to achieve a full recovery and as she still needs peace and calm, the princely couple therefore asks that their private life and family environment continue to be respected," the statement concluded.

Princess Charlene has reunited with Prince Albert and their kids. Photo / Instagram

Charlene was thought to be recovering from an unknown illness in a clinic in Switzerland – about 350km from Monaco – where she's been since November last year.

Little is known about what Charlene was suffering from, but the palace revealed in January she was undergoing "dental treatment".

Prior to that, the former Olympic swimmer suffered from an ear, nose and throat infection which saw her undergo several surgeries in her native South Africa, where she stayed for 10 months.

She was reunited with her family for the first time in months when Albert and their two children, Princess Gabrielle and Prince Jacques, visited South Africa in August.

Charlene briefly returned to Monaco in early November before she was said to have travelled to Switzerland for more treatment.

Further concerns were raised over her welfare when her children were photographed during National Day of Monaco celebrations on November 19, where they were seen holding a sign in the Monaco palace window, which read: "We Love You, Mommy" and "We Miss You, Mommy."

Charlene and Albert's marriage, which kicked off with a $100 million wedding in 2011, has been dogged by scandal, with Albert previously confessing to fathering illegitimate children and rumours swirling that Charlene tried to flee before their wedding day.

The couple first met shortly after the Olympic Games in 2000, where former swimmer Charlene, then 22, came fifth in the 4x100m medley relay.

Albert is the son of Grace Kelly, who died in a car accident in 1982.