The model and actress has been keeping a low profile since suffering a miscarriage at the beginning of May, five months into her pregnancy.
A friend of Brook's requested at the time that the 31-year-old and boyfriend Thom Evans be allowed to mourn the loss of their first child in peace.
They said: "There's nothing you can say to anyone at a time like this. She just needs to be allowed some time alone to grieve."
After a month of silence, Brook finally returned to Twitter yesterday to thank her followers for their support during this difficult time.
"Thank you everyone for your lovely messages, it means so much," she wrote, before promising: "I will be back soon xxxxxx"