Los Angeles, Star couple Chrissy Teigen and John Legend are mourning the loss of their son one month after announcing the news of her pregnancy.

Model Teigen and singer-songwriter Legend took to their Instagram and Twitter accounts to share the tragic news.

"We are shocked and in the kind of deep pain you only hear about, the kind of pain we've never felt before. We were never able to stop the bleeding and give our baby the fluids he needed, despite bags and bags of blood transfusions. It just wasn't enough," Teigen posted on Instagram along with black-and-white photos of the couple at the hospital.

"We never decide on our babies' names until the last possible moment after they're born, just before we leave the hospital. But we, for some reason, had started to call this little guy in my belly Jack. So he will always be Jack to us. Jack worked so hard to be a part of our little family, and he will be, forever," she continued.

"To our Jack -- I'm so sorry that the first few moments of your life were met with so many complications, that we couldn't give you the home you needed to survive. We will always love you," Teigen wrote.

She thanked everyone "who has been sending us positive energy, thoughts and prayers. We feel all of your love and truly appreciate you".

"We are so grateful for the life we have, for our wonderful babies Luna and Miles, for all the amazing things we've been able to experience. But everyday can't be full of sunshine. On this darkest of days, we will grieve, we will cry our eyes out. But we will hug and love each other harder and get through it," she concluded.

Legend also shared Teigen's statement on his own Twitter account, and wrote: "We love you, Jack."

After her Instagram post, Teigen tweeted: "Driving home from the hospital with no baby. How can this be real."

In September, Teigen was put on bed rest. Later, she was hospitalised due to excessive bleeding from her placenta. She recounted one ?scary morning? on September 29 after receiving blood transfusion when she experienced a ?huge blood clot".

Teigen and Legend have a daughter Luna Simone, aged four, and a son Miles Theodore, aged two.