Bride Britney Back to Bachelorette
Spears, 22, filed for an annulment just after the Clark County District Court opened, citing incompatibility with her spouse, Reuters reported.
"Plaintiff Spears lacked understanding of her actions to the extent that she was incapable of agreeing to the marriage," the annulment document stated, according to news reports.
The papers were signed by Clark County Family Court Judge Lisa M. Brown, CNN reported, making the annulment official.
"It was just crazy, man," Alexander, 22, told "Access Hollywood" in an interview Monday morning, CNN reported. "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.'"
As PEOPLE reported over the weekend, Spears was wearing a baseball cap and jeans when she married Alexander early Saturday morning at the Little White Wedding Chapel on the Strip -- though, apparently, the intention all along was to keep the union short lived.
As someone close to Spears told PEOPLE: "I don't know what's going through her mind."
The wedding plan apparently was hatched Friday night while Spears and Alexander were partying at Ghostbar, the hip club in the Palms Casino Hotel. A hotel bellman shuttled the couple to the chapel.
Chapel staff told the couple that they couldn't get married without a license, so the pair rode by limo to the Clark County Marriage Bureau office in the downtown Las Vegas courthouse at some point after 12:30 a.m. on Saturday. They applied for and were granted the marriage license, then rode back to the chapel, where they were married.