Secret love letters have revealed the intense relationship renowned French sculptor Auguste Rodin had with a young English actress almost 50 years his junior.

The artist, famous for works including The Thinker and The Kiss, fell for 23-year-old Sybil Mignon Cooke when he was 68.

Their fling was known by only their closest confidants, only now coming to light following the sale of romantic notes shared between the two.

Secret love letters have revealed the intense relationship renowned French sculptor Auguste Rodin (left) had with a young English actress almost 50 years his junior. The artist fell for 23-year-old Sybil Mignon Cooke (right) when he was 68

They first met after she arrived from Berlin in 1907.

Rodin would draw Ms Cooke - admired for her 'lovely voice, striking looks and witty charm' - every time she visited Paris en route to Germany, most often in the nude.

When she was not in his company, the much feted sculptor longed for her.

In one letter, bought by the Musée Rodin in Paris in 2010, he penned : 'Alas, my voluptuous memory does not manage to capture you; that adorable form of your youth in all its beauty which demanded my adoration as an artist and a man...I kiss your hands and very secretly your beautiful portrait.'

Rodin was generous to his English muse, gifting her two of his works. Those were a drawing of a young woman, most likely Cooke herself, disrobing, and a plaster maquette of a relief of a female bust.

He also gave her a photograph of himself.

Rodin was generous to his English muse, gifting her two of his works. Those were a drawing of a young woman, most likely Cooke herself, disrobing, and a plaster maquette of a relief of a female bust. He also gave her a photograph of himself

Rodin was most famous for his magnificent sculpting works, including The Thinker (left) and The Kiss (right)

Writing to him, Cooke said: 'They are the most precious things that I possess.'

After they spent a day shopping together - an excursion on which Rodin purchased his lover silk stockings, two blouses, gloves and a hat, she wrote: 'It was so fun to choose these little items.'

In response, he sent her another photograph, signing it with 'affectionate homage and devotion'.

Photographs were taken of the sculptor in the garden of Cooke's parents' home and in her final letter to him, in 1917, she described the visit as 'the happiest hours of [my] life'.

Despite their relationship, Cooke married Robert Hood later that year.