The actress took to Instagram on Monday to share the news, alongside a snapshot of a baby beanie with her son's name sewn onto the front.
"I am incredibly thankful and overjoyed to announce the birth of our son, Brooks Rauch, who we just welcomed into the world and directly into our hearts," Melissa, 39, wrote of her newborn son, who joins the couple's 2-year-old daughter, Sadie.
She also addressed the unique reality of welcoming a baby amid the ongoing coronavirus pandemic and shared special praise for the doctors and nurses who helped her during her pregnancy and delivery.
"His arrival was made possible, in no small part, by the front line heroes -- the nurses and doctors who show up each day to make sure that life keeps marching forward, regardless of the circumstances," she wrote.
"Words can't describe how grateful I am to have this baby boy join our family, but to say that it is a surreal time to be bringing life into the world is an understatement. Given that, I wanted to share some thoughts with other expectant mothers or 'Pandemamamas' -- as I like to call us -- who are navigating these uncharted waters," she continued, directing her followers who are interested to an essay she wrote on the subject.
"As I've previously shared, I am no stranger to loss on the road to motherhood -- so to those dealing with infertility or grieving a loss, please know you are in my heart and I’m sending you so much love," concluded the actress.
Congrats to Melissa and Winston on their new bundle of joy!