PARIS - Prince Albert of Monaco will marry his girlfriend, former South African Olympic swimmer Charlene Wittstock, in September, a French magazine said on Tuesday.

Prince Albert II of Monaco arrives with his friend, Charlene Wittstock, Olympic swimmer of South Africa, for the opening ceremony of the 12th Games of the Small States of Europe in Monaco in this June 4, 2007 file photo. Albert, who will be 50 on Friday, is expected to marry his girlfriend, former South African Olympic swimmer Charlene Wittstock, in September, a French magazine said on Tuesday. [Agencies]

A photo of the prince, who will be 50 on Friday, and 30-year-old Wittstock filled an online front-page preview of the latest edition of Point de Vue magazine, which hits news stands on Wednesday.

"While the date is not yet fixed, two sources confirm that preparations are under way for a royal wedding at the end of summer," the celebrity gossip weekly reported.

The media have portrayed Albert as a playboy with a liking for fashion shows, but he has also set up an environmental foundation. He has dated a series of models and said he wants to marry, but in his own time.

He has two children out of wedlock but, under the succession rules in the Catholic principality on the French Riviera, only children born within marriage may succeed to the throne.

The last time Monaco celebrated a wedding of its ruling prince was in 1956, when Albert's father Rainier married Oscar-winning American actress Grace Kelly.