Legend and Teigen are also parents to 15-month-old son Miles Theodore
In the shot, shared on Wednesday, Teigen, 33, can be seen posing alongside her mom Vilailuck Teigen, sporting a pink and yellow polkadot dress and big curly hair.
“We came. to slay, @pepperthai2,” Teigen captioned the post, tagging her mom.
The resemblance Teigen has to her baby girl is so striking that Legend, 40, commented, “It’s Luna!!”
Singer Melanie Fiona also joined the conversation writing, “Omg!! It’s Luna’s entire face!!!!!!” Teigen and Luna even have the same smile.
“Yes Luna is your twin, but we need @pepperthai2 anti-aging secrets. She looks exactly the same,” a fan wrote of Luna’s grandma.
While Luna may be the spitting image of Teigen, the model’s baby son Miles Theodore is Legend’s twin.
Last year, just five months after Miles was born, Teigen shared a photo of the baby hitting a major milestone as he fed himself with a spoon.
“Baby bear is eating!” she captioned the sweet shot of her youngest child.
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The couple’s celebrity friends were also taken aback at how similar the father-son duo looked, with several stars commenting on Teigen’s post, first captured by the Instagram account Comments by Celebs.
“That looks like you face swapped John onto a baby!” wrote late-night host Trevor Noah.
Legend himself also acknowledged the resemblance in February of this year after Teigen shared a photo of Miles wearing an adorably baby-sized tuxedo.
“someone had a wonderful valentine’s dinner with @alanavanderaa and @chrishimmm! maybe he will fit into these shoes by next v-day,” the mother of two, 33, captioned the images, drawing extra attention to her son’s too-big sneakers.
In response, Legend commented, “He is me,” which prompted Teigen to joke about her fidelity to her husband.
“@johnlegend it’s important to cheat with people who look like your husband,” she wrote, in an interaction highlighted by Instagram account Comments by Celebs.
Legend and Teigen tied the knot in Lake Como, Italy in September 2013.