While the British monarch is heading into her tenth decade, can you guess which young royal (whose birthday is also April 21) is just finishing up her first?
It's Princess Isabella, the second child of Denmark's Crown Prince Frederik and Crown Princess Mary.
The princess is third in the line of succession to the Danish throne – after her father and her 10-year-old brother Prince Christian.
In honor of Isabella's 9th birthday, Denmark's Royal Palace released sweet new portraits of the blue-eyed beauty, the latest in a long line of photos taken by the Crown Princess of her daughter as she grows up.
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Princess Isabella was most recently seen on the balcony of Copenhagen's Royal Palace supporting her grandmother Queen Margrethe II during her birthday celebrations on April 16.