The 34-year-old star opened up about the difficulty of breastfeeding as a working mum and also revealed the name of her new arrival.
Breastfeeding is not easy for everyone. Sometimes, it simply does not work for people while other times, there are a number of difficulties and obstacles that get in the way of a positive breastfeeding experience.
Initially, she had planned on taking six months of maternity leave, but this turned out to be impossible due to some pre-arranged work commitments.
This led to her having to be at work for six hours a day, pumping three whole feeds.
In speaking so openly about her breastfeeding experience, Knightly was able to shine a light on just one of the difficulties that women face after having a baby.
Some don't have the option to take long maternity leave which impacts their breastfeeding experience with their baby.
In order for breastfeeding to be normalized, it's so important to have people like Keira Knightly who openly chat about and discuss the reality of breastfeeding and the struggles that come along with being a new mum.
Knightly also (finally!) revealed the name of her new arrival - Delilah. Little Delilah arrived seven weeks ago, welcomed by her older sister, four-year-old Edie.