Frida Kahlo, My Birth (1932).

This weekend, the Detroit Institute of Arts opened their blockbuster exhibition “Diego Rivera and Frida Kahlo in Detroit,” a show of works by the pair centered on their brief time together in the city. But there’s one key piece missing from the show: Frida Kahlo’s My Birth (1932). Why? Because Madonna, a major Kahlo collector, refused to loan it to the museum.

One of just five works that Kahlo produced while in Detroit, the museum was unable to procure the painting from the pop star.

“We tried to get it,” Mark Rosenthal, DIA adjunct curator for contemporary art told the Detroit News. “You have no idea what we went through. But I can’t describe all that.”

DIA reportedly tried for over a year to win the star’s approval to include My Birth, in the exhibition, which tells the story of the couple’s brief time spent in Detroit (see Diego Rivera and Frida Kahlo Blockbuster at Detroit Institute of Arts Traces a Tragic Romance). In response, they received a curt email from Madonna’s publicist: “We will not be commenting on this.”

The fact that she previously lent the painting to the Tate for a 2005 Kahlo exhibit gave the curators a false sense of hope throughout their trials with Madonna’s camp.

“To many of us, her lending to the Tate was a bit of a surprise because she hadn’t lent before,” said DIA director Graham Beal. “For a moment there we thought we might have a chance, but it just didn’t work out.”

Pam Marcil, the museum’s PR Director, told artnet News: “There’s really not much to say. We tried to get the painting for the exhibition and it just didn’t work out.”

My Birth, which depicts the birth of Kahlo (an adult Kahlo), to a mother whose upper body is covered in a sheet, is apparently very important to the musician.

“If somebody doesn’t like this painting,” Madonna told Vanity Fair in 1990, “then I know they can’t be my friend.”

While Madonna managed to hang on to her Kahlo, even at the expense of an important exhibition in her home state, she hasn’t been so lucky with all of her art collection.

artnet News reported this morning that the starlet once owned several Jean-Michel Basquiat works during the pair’s brief romance in the 1980s. However, when the relationship ended, Basquiat repossessed and even destroyed some of the paintings (see Madonna Says Jean-Michel Basquiat Took Back and Destroyed Paintings He Gave Her).