Hollywood actress Selma Blair has bravely revealed her shaved head while marking the end of a course of treatment for multiple sclerosis.

The 47-year-old, who was diagnosed with MS last year, said her immune system is compromised for the "next three months at least", and that her health is the "best gift" she could give to her eight-year-old son, Arthur.

Blair posted a picture on Instagram revealing her new look while leaning against her Alinker walking assistance bike in what appears to be a hospital room.

She wrote: "Today is a banner day. I am being discharged from the care of an incredible team of nurses and techs and a visionary Dr. who believes in my healing as much as I do.

"This has been a process. And will continue to be one. I am immunocompromised for next three months at least. So no kisses please.

"I wanted to make sure any complications that might arise here were my private space. And we got through brilliantly.

"I thank you all for your love and support and that extra dose of great with a @people cover. I see things so much more clearly now. And I am excited to share this journey when I am ready. For now, I have recovery. And a great @the--alinker--world so I gotta split. Bye!!!!!!"

Referring to her son Arthur, who is celebrating his eighth birthday, she added: "This is the best gift I could give to Arthur. #newimmunesystem #whodis?"

Earlier, Blair paid tribute to her son with a picture showing him chopping off her hair.

She wrote: "I want to smell him. Tell him I am so proud of him. Hold him. And I will. Just not on his birthday. Which is today."

Reminiscing about giving birth to Arthur - whose father is fashion designer Jason Bleick - she told of the "painful induced labour" she endured to bring him into the world.

She added: "And now my kid can cut his moms hair and make jokes and assure me just by being him that I am good enough.

"Even if we aren't together for this birthday. Which makes tears well, I know he is happy with dad, dancing and playing on the beach later today. What more could I really ask for. Happy birthday. My son. I love you oceans, mama #arthursaintbleick."

Blair next appears in new Netflix series Another Life.

MS is an incurable condition of the central nervous system which causes symptoms such as vision loss, pain, fatigue, muscle weakness and impaired co-ordination.

More than 100,000 people in the UK suffer from MS, and it affects three times as many women as men.