Britney Spears says Las Vegas is partly to blame for her 55-hour marriage to childhood friend Jason Alexander.

"I totally believe in the sanctity of marriage," she said in an interview with MTV on Wednesday, before adding: "I was in Vegas and it took over me."

The pop singer expressed bemusement at the fuss her 3 January wedding caused. "We landed on Mars that day. Why aren't they talking about that?" she said.

Pressed on her feelings for Alexander, she replied: "That's personal."

But the singer did admit that the two of them "hit it off completely".

Annulled

Spears and Alexander, both 22, married at the 24-hour Little White Wedding Chapel early in the morning of 3 January.

The wedding was annulled two days later, but not before it made headlines around the world.

MTV in the US has moved Britney Spears' new video to its late-night schedule, saying it is too racy for day viewing.

The move follows Janet Jackson's controversial MTV-produced performance at the US Super Bowl in which her right breast was exposed on live TV.

In the video for Toxic, Spears wears a see-through catsuit and cavorts with a man in an aeroplane toilet cubicle.

"We always take into account what the cultural environment is on an ongoing basis," said an MTV spokeswoman.

Publicists for Spears' label, Jive Records, were not immediately available for comment.

The channel said in all it had moved six videos to its late-night rotation between 2200 and 0600.

Others include videos by alternative rock bands Blink 182 and Maroon 5, and rap-rock outfit Incubus, whose video for Megalomaniac depicts an Adolf Hitler character with angel's wings flying over a crowd.

Incubus guitarist Mike Einzigersai said: "It's ironic that this MTV scrutiny comes from an incident where someone bared their chest in public, while for the first time, our singer has his shirt on for an entire video."

Record labels for Spears and the other artists were informed of the move last week, the MTV spokeswoman said.

She denied the network was engaging in self-censorship or responding to pressure from its parent company, Viacom.

"Given the particular sensitivity in the culture right now, we're erring on the side of caution for the immediate future," she said.

Janet Jackson has apologised after her exposure caused a furore in the US, leading to complaints from 200,000 TV viewers.

The incident, during the biggest TV audience of the year, has prompted an investigation by the Federal Communications Commission. CBS, which broadcasts the Super Bowl and the Grammys, faces possible sanctions.

Spears, 22, whose fourth album In The Zone was released last November, has sold more than 54 million albums around the world since starting her recording career in 1999.

In January she took part in a wedding ceremony with childhood friend Jason Alexander in Las Vegas, but the marriage was annulled two days later.