The TV star posted an image of herself in a pink bikini on Friday to promote the launch of her summer bikini plan.
A follower asked if anyone else had noticed a mark on Lorraine’s right thigh which she assumed was a result of “airbrushing”.
Lorraine tweeted back: “Cheryl - this is a scar on my leg from a serious accident when I was trampled by a horse. Pics are untouched.”
She added shortly afterwards: “I am not as self-conscious about it now - but remarks like that do sting a bit.”
Lorraine, 56, fell from a horse four years ago and was then trampled by the animal, resulting in the need for four hours of emergency surgery.
Realising the error of her ways, the follower deleted the original tweet and posted an apology to Lorraine.
The Glasgow-born star suffered the injury to her thigh in 2012 after falling from her horse during a charity event organised by Sarah Brown, wife of former Prime Minister, Gordon.
Lorraine was training at a riding school in Surrey for the charity event in which she was scheduled to compete against Sarah in events such as riding, swimming and shooting.
She said it was a “real shock” and still suffers from pain as a result of the accident which resulted in her undergoing four hours of emergency surgery.