Lindsay Lohan has denied going clubbing hours after being sentenced to lockdown rehab.

The troubled actress was allegedly pictured hidden by a sheet in the back of an SUV arriving at the AV nightclub on Monday night.

Her reported appearance at the Hollywood hot spot came not long after she appeared in court to accept a plea deal with prosecutors in her reckless driving case.

The car was emblazoned with the Mr. Pink Energy Drink logo, which footed the bill for Lindsay to fly into L.A. on Sunday night by private jet.

“Guys relax, that was NOT me at AV or in the @Mr. Pink SUV,” she tweeted on Tuesday. “I'm taking this seriously and focused on the road ahead.

"I stayed in last night, after a pretty long day ... and ordered sushi to my hotel. Don't believe EVERY little thing you hear, unless you hear it from me. The support I have gotten, has been great and means a lot.”

The 26-year-old Mean Girls star is scheduled to enter a stay rehab facility for 90 days in addition to 30 days of community labour and psychotherapy for 18 months.

Lindsay has been in and out of rehab and faced a string of drinking and drug convictions since 2007.

In court, the actress pleaded no contest to misdemeanour charges of reckless driving, lying to police and obstructing police from performing their duties while investigating her 2012 car crash in Los Angeles.

The outcry over her alleged nightclub appearance came after X17 online acquired incriminating photographs purporting to be of the star.

After seeing the photographs, Lindsay’s father Michael Lohan fumed that his daughter is not taking her impending treatment seriously.

“Just when you think things are getting better, the same people who were in court with Lindsay, and heard the judge instruct her not to be around people or places that drugs might be present, are the same ones out with her attempting to go into a club last night!” he seethed to Radar Online.

Meanwhile, Lindsay’s former assistant Gavin Doyle did not show up for a scheduled meeting with prosecutors who are investigating allegations of witness tampering.

A law enforcement officer told Radar Online that Gavin was due to meet with Los Angeles City Attorney Terry White on Tuesday to discuss allegations that Lindsay’s lawyer Mark Heller “wanted him to change his testimony” at Lindsay’s trial.

“It’s been alleged that Heller instructed Mr Doyle to say photographers were chasing the car Lindsay was driving prior to their crash last year and that he grabbed the steering wheel, causing Lindsay to smash into the cement dump truck,” the source claimed.

However, Gavin did not show up for the meeting and Mr White is “now evaluating his options,” according to the insider.

Radar reports that the case is likely to be referred for investigation to the New York State Bar, where Mr Heller has a legal licence.

Gavin was said to be a passenger in Lindsay’s Porsche last summer when she crashed in Santa Monica, California.

Radar states that Gavin would have testified that Lindsay was the one driving the car at the time of the accident, contradicting her claims that she was not behind the wheel.

The website says he had been fully co-operating with prosecutors and was expected to be a “key witness” at the trial had it proceeded.

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