Image copyright AFP/Getty Image caption The actress said she has had symptoms for "15 years at least"

US actress Selma Blair has revealed she has multiple sclerosis (MS) in an Instagram post.

The 46-year-old Cruel Intentions star said she was diagnosed in August but has had symptoms for years.

"I am disabled. I fall sometimes. I drop things," she wrote, calling the news "overwhelming in the beginning".

Multiple sclerosis is an incurable condition affecting the brain or spinal cord, causing vision, balance and muscle problems.

According to the UK's NHS, it is two to three times more likely in women than men, and is usually diagnosed in people in their 20s and 30s.

The cause of the condition is still unknown.

Blair is set to appear in the Netflix programme Another Life, and said the "profound" help she received from costume designer Allisa Swanson had inspired her to come forward with the story.

In her post she said she was "in the thick of it" but hoped to give hope to others by talking about the condition.

Despite the news, the actress said she was relieved to finally receive the diagnosis.

"My memory is foggy. And my left side is asking for directions from a broken GPS. But we are doing it," she wrote.

"I want to play with my son again. I want to walk down the street and ride my horse. I have MS and I am ok."

Blair also starred in Legally Blonde and the Hellboy series.

There is no cure for MS, but treatment can help manage symptoms. This may include painkillers or drugs to reduce nerve inflammation, physical therapy to ease muscle stiffness, or medication to slow the condition's progression.

On social media, many living with the condition sent support to Blair - among them journalist Victoria Brownworth, who thanked her for helping to demystify it.

"I was dxd [diagnosed] with MS at 30," she wrote. "I can so relate to how #SelmaBlair feels."

Actress turned activist Rose McGowan also tweeted her best wishes, writing: "You are a stellar being, Selma Blair. Your truth and honesty will help so many. Blessings on your journey."

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How are readers coping with the condition?

A selection of your messages on the subject of MS:

Tash Castle, Lincolnshire

Tash says she was diagnosed with MS in February 2018, at the age of 46.

She says that while initially she was upset by the diagnosis, she "very soon realised that it is not the end of the world," and avoids the attitude of "being too woe is me".

Tash looked online for support: "I've visited a lot of forums and found them to be helpful."

Krystyna Armer

Krystyna says that she "resonates so deeply with Selma Blair's Instagram post".

"I'm a mum for the first time and becoming a parent is challenging when you already cope with issues such as fatigue," she says.

However, Krystyna urges those with MS not to despair: "If people are understanding, you can get through it however tough."

Karen Vogelsang, York

"I had an MS flare up at 23 in 1988," Karen says. "I lost the feeling from the waste down for 8 weeks, which was very scary."

Karen says that the diagnosis "hit hard at first".

She has "found cycling is good therapy" for managing her symptoms.

Sarah Iveson, Nottingham

Coming to terms with having MS has been a "journey full of crying and fear," says Sarah.

However, hearing other people speaking about having the illness has helped her feel more comfortable about her diagnosis.

Sarah says that reading Selma Blair's story "really helps" and made her "want to stand up and talk" about what she goes through with the condition.