Princess Charlotte Holds A Butterfly In Precious Photo Shared By Kate Middleton, Prince William

Prince William and Kate Middleton surprised fans with a sweet new photo of their only daughter, Princess Charlotte.

On Saturday, the Duke and Duchess of Cambridge posted a snap of their 6-year-old daughter gently cradling an orange and black butterfly in her hands while standing in a patch of flowers. In the photo, the young princess is dressed casually in a blue T-shirt and pink floral pants.

"We wanted to share these beautiful Peacock and Red Admiral butterflies as part of Big #ButterflyCount initiative taking place across the UK," posted Prince William and Middleton alongside the photo on Instagram.

The initiative is an effort by British charity Butterfly Conservation and encourages U.K. residents to "assess the health of our environment simply by counting the amount and type of butterflies (and some day-flying moths) we see," according to its website.

"@savebutterflies are encouraging us all to count these incredible creatures because not only are they beautiful creatures to be around but they are also extremely important. Butterflies are vital parts of the ecosystem as both pollinators and components of the food chain. Hopefully you can beat last year's total, @savebutterflies," the couple wrote, adding a butterfly emoji to the post.

According to the U.S. Forest Service, the red admiral butterfly that Princess Charlotte is holding in the image is found in North and South America, Europe and Asia and is the most popular butterfly in urban areas.

Royal fans were happy to get a new photo of Princess Charlotte, and they also thanked Prince William and Middleton for spreading awareness on the initiative.

"This is wonderful and brings positive vibes," one person commented. "Beautiful photos and cause. Thank you for sharing," another Instagram user wrote.

"So adorable and for a great cause!" a third user wrote with a red heart emoji. "We have a perfect Princess Charlotte, thank you K&W for this amazing English rose you gave to us," another royal supporter commented.

The last photo Prince William and Duchess Kate shared of Princess Charlotte was in honor of her birthday in May. The snap showed Charlotte grinning at the camera as she posed in a blue Rachel Riley dress with pink floral detail, People reported.

Some royal fans noted that Princess Charlotte is taking after her great-grandmother, Queen Elizabeth, in looks as she grows older.

"She looks a lot like the Queen!!" one person commented on the birthday portrait.

"She looks exactly like her Great Grandma the Queen!" another added.

The Duke and Duchess of Cambridge's children have also been photographed during outings with them in the past several weeks.

In June, Prince George and Princess Charlotte spent time with their dad at Queen Elizabeth's Sandringham Estate, Town & Country reported. The siblings helped kick off a half-marathon Father's Day race at the monarch's private, Norfolk home.

Middleton and Prince Louis did not join them, but the couple's older children stuck with their dad as they counted down the start of the race and cheered on all of the runners.