Ashley Graham has made naps “non-negotiable” during her pregnancy. Picture: Reuters

Ashley Graham has made naps “non-negotiable” during her pregnancy.

The pregnant model is expecting her first child with husband Justin Ervin, and took to Instagram on Monday to share a video of herself taking a quick nap while on a beach chair in a black bikini, as she insists extra sleep is a must while she’s carrying her baby.

She wrote alongside the clip: “Naps are a new non-negotiable @lebarthelemy (sic)”

Ashley, 31, announced her pregnancy last week, when she posted a sweet video which also marked her and Justin’s nine-year anniversary.

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Naps are a new non-negotiable @lebarthelemy

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She wrote: "Nine years ago today, I married the love of my life. It has been the best journey with my favorite person in the world! Today, we are feeling so blessed, grateful and excited to celebrate with our GROWING FAMILY! Happy anniversary, @mrjustinervin Life is about to get even better. (sic)”

And just a few days ago, she took to social media again to share a candid image of her stretch marks, where she wrote: "same same but a little different (sic)”

The post was met with compliments and supportive messages from her fans, as well as celebrities including model Lily Aldridge and actress Niecy Nash, who both left a series of red heart emojis, and Lady Antebellum singer Hillary Scott, who commented, “My Lord, THANK YOU for this. (sic)”