The initiative, launched by Butterfly Conversation, is a UK-wide survey that aims to help assess the health of our environment by simply counting the amount of butterflies we see.
In the photograph, Princess Charlotte, six, is pictured cupping a Red Admiral butterfly in her hands. She is wearing a blue T-shirt and a pair of floral pink shorts.
Two other photos show some close-up shots of Peacock butterflies on a spray of lilac.
The images were taken close to the Cambridge’s home in Norfolk.
In the caption, the Cambridges explained how they were taking part in the Big Butterfly Count and encouraged others to do the same.
“We wanted to share these beautiful Peacock and Red Admiral butterflies as part of Big #ButterflyCount initiative taking place across the UK,” they wrote.
“Butterfly Conservation 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. Hopefully you can beat last year’s total @savebutterflies!”
The Big Butterfly Count started on 16 July and is due to conclude on Sunday.
It works via an app that allows participants to submit their individual butterfly counts.
Those who choose to take part are also given a butterfly ID chart to help them identify the butterflies they spot.
The Big Butterfly Count was launched in 2010 and has quickly become the world’s biggest survey of butterflies.
More than 111,500 people took part in 2020, submitting 145,249 counts of butterflies and day-flying moths from across the UK.
Find out more about the Big Butterfly Count here.