Lindsay Lohan on best behaviour

Lindsay Lohan was on her best behaviour while filming 'Anger Management'.

The 26-year-old actress - who was sentenced to 90 days in a rehab facility last week for lying to police about driving during a car crash last June - 'shocked' crew members by showing up early on set in recent days and being extremely professional.

A source told Us Weekly magazine: 'She has showed up on time and early, and she has been very prepared and professional. Everyone is shocked -- the crew had already planned to stay late in case she was late or didn't show up, but so far, so good!'

The troubled starlet - who has been to rehab five times since 2007 - also took some time away from filming to meet a crewmember's children.

The insider said: 'Lindsay said, 'Oh, I'd love to meet them!' She went over and said hi and was really sweet to them.'

The actress filmed a guest role for the show this week after being invited to do so by her good friend Charlie Sheen, who is the show's star.

The duo became firm friends after filming a cameo for 'Scary Movie 5' last year and Charlie, who has repeatedly supported the actress, even gave her $100,000 to pay a tax bill.

But the insider revealed that there is a possibility she will be back on the show again once she completes her court ordered rehab and 30 days of community service, saying: 'She is only in one episode but is hoping to do more. There is a possibility she'll be asked back.'

On Tuesday (26.03.13) the actress revealed on Twitter that she really enjoyed the experience.

She wrote: 'I just had such a wonderful day on set of #angermanagement with @charliesheen & @LIGHTAARON @SaveTheSociety @jazejazz7 and the entire crew!'

Lindsay has now flown to Brazil, where she is set to earn more than $100,000 to promote a clothing company.