Chrissy Teigen and John Legend have announced the arrival of their first child together – a baby girl.

Teigen shared the happy news on Instagram, posting a picture of a screen displaying the weight of the new addition to their family with the caption, "She's here! Luna Simone Stephens, we are so in love with you! And sleepy. Very sleepy."

Legend also announced the arrival of their first child on Twitter, saying that he and his wife "couldn't be happier!"

The couple, who married in 2013, announced the news of Teigen's pregnancy in October 2015 by sharing the same black and white image to their Instagram accounts.

While sharing the news, Teigen opened up about her difficulty in conceiving saying, "John and I are so happy to announce that we are pregnant.

"As many of you know, we've been trying to have a baby for a while now. It hasn't been easy, but we kept trying because we can't wait to bring our first child into the world and grow our family. We're so excited that it's finally happening. Thank you for all your love and well wishes. I look forward to all the belly touching."

Legend, real name John Stephens, captioned his photo simply, "We're pregnant!"