Britney Spears speaks out after lounging on car roof while on the freeway

Britney Spears has spoken out after she was spotted lounging on a car roof as it drove down the freeway.

The singer was seen poking her upper body out of a black SUV near Studio City on Thursday as it drove along. The car was reportedly travelling at about 45 miles per hour.

"What people see is two seconds of insanity of me arching me to the lords !!!!!" the 44-year-old wrote on Instagram. "Yet the days and hours of my reality !!!!!! Nothing is what it seems. Psss, I think I need to come out of the roof quite a bit more."

Before her comment on social media, a source told the Daily Mail, "Britney just went through the sunroof for a quick moment. She wanted to see what the traffic was about up ahead because the cars came to a stop. She wanted to see how long they would be delayed."

They added that the Toxic singer "used to do this all the time as a kid growing up in the South," and said the star "didn't mean to do anything bad."

This latest incident has raised concerns about the star's wellbeing. In March she was arrested for driving under the influence, after she was seen driving "in and out of lanes" and speeding. The 911 audio heard that she was "erratically braking, swerving and driving with no taillight."

In May, TMZ reported Spears was seen "screaming," "barking" and walking while holding a knife at Sherman Oaks' Blue Dog Tavern.

Her rep explained the incident, saying, "Britney was enjoying a quiet dinner with her assistant and bodyguard. She was simply telling the story about how her dog was barking at the neighbours. At no point did she put anyone in danger with a knife. She was cutting her hamburger in half."