The mysterious American Express Centurion, otherwise known as the Black Card, is unlike most credit cards: The invite-only slice of anodized titanium is designed for the super rich.

Details are limited but, in order to get this exclusive card, the main thing you need is a well-padded bank account — and celebrity status doesn't seem to hurt. Both Kim Kardashian and Oprah Winfrey reportedly have one, and Jerry Seinfeld broke his out in a recent episode of the Netflix show, "Comedians in Cars Getting Coffee."

In fact, were it not for Seinfeld, the card might not exist. "Do you know why there is a Black Card?" he asks fellow comedian John Mulaney. "Me."

As Seinfeld tells it, when he was a spokesperson for American Express in the 1990s, a member of the crew at a shoot once asked him if he had the Black Card.

"There's only three in the world," the man said. "The Sultan of Brunei has one, the president of American Express has one, and I thought you would have the third one." The next day, Seinfeld says, he called up the president of American Express, who told him the card doesn't exist but that maybe it should.

When the company finally issued the card in 1999, Seinfeld got the first one.