President John F. Kennedy

The love letters that John F. Kennedy wrote to Gunilla von Post, a beautiful Swedish woman, will be sold at auction, according to ABC news.

The steamy letters will start at $25,000 although bidding may go as high as $100,000.

The couple met on the French Riviera in 1953 when he was 36 and she was 21. They had an immediate attraction to each other.

That attraction lasted long after he married Jacqueline Bouvier, but that did not stop Kennedy from continuing to write to her and seek her company.

On June 28, 1954, the summer after he was married, Kennedy wrote to Von Post: “I might get a boat and sail around the Mediterranean for two weeks - with you as crew.”

In November 1954, ABC reported, Kennedy wrote from a New York hospital where he was undergoing back surgery a letter “full of longing.”

He wrote: “I am still in the hospital after two months. I was terribly disappointed that at the last moment I was not able to come to Europe, especially when you were going to be in Paris and we could have had such a good time.

“Is there any chance you will be coming to the U.S.?”

Von Post, now 78, said JFK’s letters made her heart go “boom-boom-boom-boom.”

“I was very happy to hear from him, but I said, ‘he’s a married man,’” she told 20/20.

However the following year they had a week together at a Swedish Castle.

“I borrowed him for a week, a beautiful week that no one can take away from me, from that,” she told ABC. However it did not last.

In his last letter in August 1955, Kennedy wrote, “I just got word today - that my wife and sister are coming here. It will all be complicated the way I feel now - my Swedish Flicka. All I have done is sit in the sun and look at the Ocean and think of Gunilla & All, Love, Jack.”