After 55 hours of marital madness and publicity gone wild, Britney Spears (search) and temporary husband Jason Allan Alexander (search) decided Monday to scrap "I do" for "I wish I hadn't."

She didn't get a ring or a fairy-tale wedding. He didn't get any of her fortune. But the 22-year-olds did forever etch themselves in the annals of ill-advised Las Vegas (search) marriages.

Talk about whirlwind. The two might have performed the quickest marriage-to-annulment escapade in the history of Sin City.

"That was fast," said attorney Brian J. Steinberg, who practices family law in Las Vegas. "I'm not even sure they had time to have sex."

Clark County Family Court Judge Lisa M. Brown signed the annulment order, and her decree was filed at 12:24 p.m.

"There is no marriage now," Spears' attorney, David Chesnoff of Las Vegas, told The Associated Press. "Jason agreed to this completely. They've made a wise decision. I know they care about each other. They are friends."

It took the judge about two hours to act on the "complaint for annulment" filed in Family Court at 10:12 a.m.

"Plaintiff Spears lacked understanding of her actions to the extent that she was incapable of agreeing to the marriage," the annulment petition said.

The pop superstar married Alexander -- who hails from Spears' hometown of Kentwood, La. -- about 5:30 a.m. Saturday at a Las Vegas wedding chapel. She was not intoxicated during the ceremony, according to a friend who spoke to her several hours afterward.

She woke up that morning a "little stunned" that she tied the knot, according to the friend, who spoke on condition of anonymity.

Alexander said he and Spears hatched the idea to get hitched early Saturday morning.

"It was just crazy, man," he told "Access Hollywood" in an interview at his home Monday morning. "And we were just looking at each other and said, 'Let's do something wild, crazy. Let's go get married, just for the hell of it."'

According to the petition, "Before entering into the marriage the plaintiff and defendant did not know each other's likes and dislikes, each other's desires to have or not have children, and each other's desires as to state of residency. Upon learning of each other's desires, they are so incompatible that there was a want of understanding of each other's actions in entering into this marriage."

Marriage is a legal contract. An annulment acknowledges that there was some inherent problem with the contract or how it was executed, said Steinberg, the lawyer. An annulment makes a marriage go away as if it never happened, while a divorce recognizes that it did occur.

Steinberg said the longer the two waited, the harder it would have been to get an annulment.

"The only reason they are getting it done so quickly is that both parties agree," he said. "I can imagine there are reasons to getting this thing done lickety-split. If you don't, the longer you let this thing sit there more it could turn contested."

Spears' record label, Jive, released a statement saying that Spears and Alexander "took a joke too far." Calls to Spears' representatives were not returned.

Spears and Alexander, a junior at Southeastern Louisiana University in Hammond, La., traveled by limousine to the Little White Wedding Chapel on the Strip after a stop at the Ghostbar, a club in the Palms Casino Hotel. The chapel staff told the couple they couldn't get married without a license, so they were taken to get a license and driven back to the chapel, where they were married.

The bride wore a baseball cap and torn jeans down the aisle and was escorted by a Palms limousine driver.

Employees at the chapel declined comment.

Spears snuck out of the Palms hotel early Monday morning.

The singer released her fourth album, "In the Zone," in November. It debuted at the top of the album charts. She begins a concert tour March 2 in San Diego.