The Office star Lucy Davis has announced she has breast cancer which has spread and is incurable.

The 53-year-old British actress shared on social media the cancer is now in her spine, right hip and ribs and it is too late for chemotherapy.

Davis is most famous for her role as the receptionist Dawn Tinsley on the popular British version of the comedy which ran from 2001 to 2003.

She was diagnosed with stage 4 breast cancer a year and a-half ago, she wrote.

"The initial lump that I felt, wasn’t a 'lump' as such; rather a kind of hard spot. Really tiny. I almost didn’t bother getting it checked. So I guess I’m saying don’t ignore anything - get everything checked out," a post to her Instagram on Wednesday morning read.

"As of now, I’m trying to live out whatever might be left of my life in as fun a way as I possibly can. I always like to find the teachable moments in anything negative that happens. And cancer has not disappointed in that regard; there’s a lot I have learned from it, and I’m grateful for that.

"As some of you will know, the pain can really be something else. Standing and walking for too long a time can be hard, and I need to use a wheelchair sometimes (so if you see me toddling around in one, feel free to give me a push!)"

"The thing that has been most vital to me is humour. I asked my friends and family to make fun of me as much as possible (which they’re really good at), and most importantly of all to not treat me like a sick person. There’s nothing that will make you feel more unwell than being treated as if you’re unwell.

"I’m not scared of whatever comes next. I’m at peace with it. I’ll see my [dog] Gracie sooner than expected, and for me, leaving my physical body just means going home. Any and all grieving is for my family; it’s far harder for them than for me."

Davis wrote that she intended to keep on doing work on animal rights and acting for as long as she can.