Shocking: Two of Marie Antoinette's four children were fathered by her Swedish diplomat, secret love letters reveal

A portrait of Marie Antoinette by  Louise Élisabeth Vigée Le Brun, 1783.

Secret letters published for the first time have revealed that two of Marie Antoinette's children were fathered by a Swedish diplomat, and not the ill-fated King Louis XVI, MailOnline reports.

According to British historian Evelyn Farr, who researched archives throughout Europe to support his assertions, Marie Antoinette had a 20 year affair with Swedish Count Axel von Fersen. She claims their 20 year affair culminated in the birth of her youngest daughter Sophie and the young dauphin Louis-Charles.

Sophie was the royal couple's fourth child. She died just weeks before her first birthday while her elder brother Louis-Charles died aged 10, during his imprisonment by French revolutionaries.

The correspondence, which has been cross-referenced with other historical documents, many unpublished, confirms unequivocally their passionate and enduring love affair. 

Farr's expose will be will be published this March for the first time in I Love You Madly - Marie Antoinette: The Secret Letters.