The 56-year-old Emmy Award winner took to Instagram to share a cheeky photo which shows her with a faux moustache on her face. "Chemo #2: finito," she wrote, clearly indicating she had commenced chemotherapy.
Dreyfus went on to reference a Katy Perry song, which she is using as inspiration to stay strong during this difficult time.
"We are NOT f**king around here. 'I’ve got the eye of the tiger. The Fighter dancing through the fire cuz I am a champion and your’re going to hear me ROAR.' Thanks to @mrtonyhale& @timothycsimons & @katyperry for their hilarious and loving inspiration," she captioned the snap.
Fans were quick to respond with positive comments below her post. "You got this! Kick it Woman!" one offered.
While another wrote: "You're going to do this, Julia!! Prayers for you!"
One more follower even shared her own story of survival. "I’m an 8 year survivor. Did chemo, surgery and radiation and beat that shit at age 25! Now I’m a breast surgeon and I just adore you! You got this girl! You will survive this :) "
This update comes after Dreyfus announced her diagnosis at the end of Septemeber.
At the time she shared a note on Instagram which read, "1 in 8 women get breast cancer. Today, I'm the one."
She also assured fans that she has a strong support network, sufficient health care and is positive about a good outcome following treatment.
Sending the Seinfeld and Veep star all the best throughout this journey.