Lindsay Lohan has tweeted she is ''pregnant''.

The troubled star, who was recently sentenced to a nine-month stint in rehab to begin later this year, took to her Twitter yesterday (01.04.13) to share the shocking message with her followers.

However, it is unsure whether Lindsay was playing an April Fool's prank or not since the tweet was posted several hours after the midday cut-off for jokes, and she has only just begun dating her current boyfriend Avi Snow.

She wrote: ''It's official. Pregnant... (sic)''

The comment has since been re-tweeted over 12,000 times, with followers picking up on the date and tradition.

One user wrote: ''Nice try! #AprilFools (sic)''

Another added: ''It's still April 1st in California, whew! (sic)''

Meanwhile, the 26-year-old actress has reportedly demanded Adderall - used to treat attention-deficit/hyperactivity disorder - during her time in rehab, which she will attend after pleading ''no contest'' to charges for lying to police about driving during a car crash last June.

Lindsay has spent the last week making the most of her freedom in Brazil, partying and making promotional appearances before entering the treatment facility.

The 'Liz & Dick' star is also said to be planning a trip to Australia, hoping to make TV appearances and some extra cash while she is Down Under.