"The Good Son: JFK Jr and the Mother He Loved" reveals John’s affair with pop star.Wikimedia

A biography of John F Kennedy Jr reveals details of a 1980s affair between the son of the famous US president and pop star Madonna.

Author Christopher Anderson writes in his book, "The Good Son: JFK Jr and the Mother He Loved" that the superstar “went after” Kennedy. She told friends that she believed an affair with him “would be nothing less than cosmic.”

While alone at the Kennedy Hyannis Port estate, near Cape Cod in Massachusetts, Kennedy and Madonna shared cocktails from specially engraved glasses obtained from the family’s first trip to Ireland after the assassination of President Kennedy in November 1963.

The six-acre compound was the “only place” the couple could “let their guard down.”

"Inside the compound, they curled up by the fire, sipping daiquiris from Waterford Crystal glasses marked 'Caroline' and 'John-John,’” writes Anderson.

Four years after John F Kennedy’s assassination, Jackie took her children to Ireland for a month-long private holiday, the Irish Independent reports.

The former First Lady said at the time that she came to Ireland to fulfill the wishes of her late husband, who had vowed to return to the country with his family after his visit there in June 1963. Jackie and her children stayed at County Waterford's Woodstown House, a secluded country home. The crystal glasses were souvenirs from their trip there.

In the biography, Anderson examines the close, and at times tumultuous, relationship between Jackie and her son.

He writes that “John-John,” as he was sometimes called, began dating Madonna in 1988 shortly after the end of her marriage to Sean Penn. Jackie vehemently disapproved of the relationship.

"There were many things about Madonna that rubbed Jackie the wrong way, not the least of which was her habit of thumbing her nose at Roman Catholic rituals. Across the globe she was being condemned as a heretic,” he writes.

He also suggests that the blonde sex symbol was a reminder to Jackie of her late husband’s affair with Marilyn Monroe.

The book also says that on the day John brought Madonna to the Kennedys’ apartment to meet his mother for the first time, the pop singer boldly signed herself in the guestbook as “Mrs Sean Penn.”

Anderson claims that Penn once confronted Kennedy at a party held for Robert De Niro at the Tribeca Grill. When John went over to introduce himself, the actor said: "I know who you are. You owe me an apology."

The affair between Kennedy and Madonna eventually fizzled out. John would eventually settle down and marry Carolyn Bessette.  

Tragically, Kennedy and Bessette would both lose their lives in a plane crash in 1999.

* Originally published in November 2014.