The BBC judge sought advice from a doctor last week after fans told her they spotted lumps around her armpit as she appeared on the expert panel.
Now, she's updated those who were concerned, sharing a post which was captioned: "Lump [and] Body MOT for women."
Watch the Insta video below:
She added: "Dear All thank you so much for making me aware of a lump you all saw under my arm. I am so grateful to have so many beautiful kind caring humans looking out for me.
"I will be popping to the hospital Friday for full blood work. Hormones could be the reason for exhaustion, sleepless nights and a few more things going on."
She added: "I’m so happy I went for a check up today. Ladies let me know how your hormones are ? Do you self check ? Hugs to all #breastcheck #hormones."
She said in a video: "Hi everyone, I just wanted to say I popped to the doctor this morning.
"She did an underarm test and breast test. She couldn’t feel anything although she also thought that she saw something when I lifted my arm up so... maybe it was cameras, lighting, not sure."
Shirley added that they'd discovered that her hormone levels are "all over the place" so she will be having full blood work done at the hospital on Friday."
In response, Shirley was flooded with messages of support, including one from her co-star, pro dancer, Katya Jones, who wrote: "Thank you for your honesty and raising awareness for women Shirley."
The show's host, Claudia Winkleman, replied with a string of heart emojis.
Shirley has been open about the fact there is a history of cancer in her family, and that she has had two scares in the past - most recently in June when she found a lump in her shoulder.
We're wishing Shirley all the best - how brave of her to speak so openly in a bid to help others!
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