The skin-tight, flesh-colored dress Marilyn Monroe wore when she sang the line “Happy Birthday Mr. President” is expected to go for as much as $2 million when it’s put up for auction in November.

Monroe, one of the most famous figures and sex symbols of the 20th century, donned the backless, rhinestone-studded and Jean Louis-designed gown while singing “Happy Birthday” to then U.S. president John F. Kennedy at a Democratic fundraiser held at Madison Square Garden on May 19, 1962.

The performance, held in front of 15,000 spectators who could have mistaken Monroe for nude, was so intimate and genuinely heartfelt it seemed to further ignite long-standing rumors of an alleged affair between Monroe and the 35th president.

Marking one of the blonde bombshells last public appearances before her death three months later, Monroe’s breathless rendition of the song has lived on and Beverly Hills-based Julien’s Auction believes it could fetch as much as $2 million.

According to Reuters, late fund manager Martin Zweig purchased the dress in 1999 for $1.26 million and he saw it as an investment. Zweig reportedly preserved the dress’ condition in a climate-controlled display case and adorned by a mannequin.

Upon her death, Monroe originally left her belongings to famed acting coach Lee Strasburg, according to Vanity Fair, and when Zweig purchased the dress it was a record price for any “single item of personal clothing.” For example, the report said, a dress belonging to the late Princess Diana of Wales went for $225,000 in 1997.

Darren Julien, president and chief executive of Julien’s Auctions, likened the dress to famous works of art and said how well it encapsulates the memory of Monroe.

"It's like the equivalent of a Monet, just because of its historic significance and its connection to one of the most important actresses of our time," he told Reuters.