Chrissy Teigen has revealed she had been struggling with post-natal depression since the birth of her daughter Luna last year.

The model and presenter said she wanted to open up about her experiences to show that the condition "can happen to anybody".

In an open letter to US Glamour, Teigen described how she had spent long periods shut in the dark and feeling unable to leave the house.

The star, who is married to singer John Legend, described her confusion as she tried to come to terms with her feelings of misery despite her joy at her "perfect" daughter.

"I had everything I needed to be happy. And yet, for much of the last year, I felt unhappy," she wrote in the article.

"I have a great life. I have all the help I could need: John, my mother (who lives with us), a nanny.

"But postpartum does not discriminate. I couldn't control it. And that's part of the reason it took me so long to speak up: I felt selfish, icky, and weird saying aloud that I'm struggling. Sometimes I still do."

Teigen, who is known for her bubbly and forthright views on Twitter, said that she is now taking an antidepressant and is also in therapy.

"I'm speaking up now because I want people to know it can happen to anybody and I don't want people who have it to feel embarrassed or to feel alone," she wrote.

"I also don't want to pretend like I know everything about postpartum depression, because it can be different for everybody.

"But one thing I do know is that - for me - just merely being open about it helps."