Princess Charlene returned to Monaco on Monday after spending several months in her native South Africa where she underwent surgery, a palace source said.

The Zimbabwean-born princess, 43, had been rushed to hospital in Durban, South Africa, in September after collapsing as the result of complications stemming from an ear, nose and throat infection.

The operation went "very well", a source said at the time.

She had already undergone surgery in August, but no details concerning that operation have been released.

Lifestyle magazines across Europe have speculated feverishly that the royal couple could be headed for divorce.

Princess Charlene has been in South Africa for most of this year, saying she was forced to stay for medical reasons, though media reports suggests she is looking for a house there.

The former South African Olympic swimmer married Prince Albert II in 2011, after first appearing with him at the 2006 Winter Olympics in Turin.

Soon after they got married rumours emerged, denied by the royal palace, that Charlene had tried to escape on the eve of the wedding.

There have also been claims that she consented to going ahead with the ceremony only after the prince agreed to an exorbitant divorce settlement should she decide later that she wanted to leave after all.

Her last public appearance with Albert in Monaco was in January. On August 25, she posted pictures with her husband and children on Instagram.

Albert, 63, is the son of Prince Rainier III and Grace Kelly, an American film star who died in a car accident in 1982.