In honour of International Women's Day on Tuesday, the actress revealed that the couple are struggling to have a child after undergoing four rounds of gruelling fertility treatment.
WATCH: Downton Abbey's Jessica Brown Findlay shares IVF heartache
Sharing a video of herself taking hormone injections, the 32-year-old wrote: "Happy International Women's day! We do hard things and then go dancing x."
She added: "IVF has made me even more aware of just how much women are capable of and what we can achieve whilst going through pain and heartbreak.
"Your body is not the enemy. Love it. No matter what. Sending love and support to every woman I have ever met and all the ones I haven't but know what this is."
The star concluded the message with: "I thoroughly recommend doing it all in Vintage Clothing. Love. Love. Love. #iwd2022 #ivf #fourrounds #recurrentpregnancyloss #vintage."
Jessica with her husband Ziggy
Her followers rushed to post messages, with many applauding her candour. "Thank you for showing this! I wish you all the luck and happiness going forward! You are tougher than anything life will throw at you," wrote one fan.
Another stated: "You're amazing. Sending love and strength and a massive whoop whoop to vintage clothing!" A third post read: "Jess, you are a gem. It is a real taboo and not talked about enough. Much love and luck to you." A fourth person wrote: "Can totally relate, thanks for your vulnerability, you incredible warrior woman you! Sending up some prayers x."
Jessica secretly got married to fellow actor Ziggy in September 2020, just two days before her 31st birthday - and the bride looked absolutely flawless in a vintage-style gown! She gave fans a glimpse into her special day in a series of images posted on her Instagram account.
During a candid chat with The Telegraph, Jessica confessed she had high hopes for 2020. "My ambition this year was to do more dancing, travel more, and work really, really hard. Whoever's up there was like, 'Ha!'" She added: "We had to cancel our wedding, which was a bit of a hit."
Like this story? Sign up to our HELLO! newsletters to get other stories like this delivered straight to your inbox.