Allen, 33, told her social media followers that she had accidentally taken the drug ketamine at the Glamour Awards in 2008 after someone asked Twitter users for the "best reason you've been kicked out of an event, building or group", reports mirror.co.uk.
The singer wrote: "Someone gave me a line of what I assumed to be cocaine at the Glamour Awards once, but it turned out to be ketamine. I was thrown out (passed over some railings) of the Glamour Awards for being in a k hole."
Ketamine is a powerful anaesthetic which can cause a loss of feeling in the body, paralysis of the muscles and it can distort reality for users.
She added: "Obviously I couldn't talk or direct the driver. So my assistant instructed the occupant of the car behind to 'follow that cab'. I believe the occupant was chattyman, I have no idea what happened next."
Comedian Alan Carr then wrote back: "I followed in the car behind with her brother Alfie - but we somehow got there before her but then she was put straight to bed and I remember helping myself to a vodka and chatting with Alfie and Sam Sparro most of the night."
She also retweeted images of herself slumped over as she was carried out by two security guards and put into the back of a car.
But some of her shocked followers criticised her for "glamourising" drug use by sharing the story.
One follower responded: "Is this really something to glamourise/be proud of?" Allen fired back: "Probably not, did you have a point?"
"There are people responding to this with phrases like 'goals' and 'hilarious'... My point is that could have a damaging affect and glamorising drug taking (and misuse) could be dangerous. Something for you to maybe consider."
Another social media user wrote: "What a brilliant role model you are! I certainly wouldn't want any child of mine to look up to you or be inspired by you. Is there a new book to promote."
Another user responded: "And you're glamourising and normalising drug use. Your children must be so proud."
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)