Prince Oscar of Sweden Celebrates His 4th Birthday — See the Sweet Photos!

Prince Oscar is growing up so fast!

As the prince rang in his 4th birthday on Monday, the Swedish Royal Family shared two adorable black-and-white portraits of the young royal on their official Instagram account. In one, he is smiling as he gazes out a window (looking just like his father Prince Daniel!) and in another he poses with his big sister, Princess Estelle, 8.

“Today, Prince Oscar turns 4!” the post was captioned.

Prince Oscar is youngest child of Crown Princess Victoria and Prince Daniel, making him third in line for the Swedish throne after his sister.

RELATED: Princess Estelle of Sweden Is a Disney Princess Come to Life in New 8th Birthday Portraits!

Princess Estelle and Prince Oscar | Linda Broström/Kungliga Hovstaterna
Princess Estelle and Prince Oscar | Linda Broström/Kungliga Hovstaterna

The pictures were taken in mid-February at Haga Castle outside Stockholm, where Estelle and Oscar live with their parents.

Just last week, Princess Estelle celebrated a birthday of her own, as the royal family also shared portraits of her and her brother for her 8th birthday. Days before that, Princess Leonore, Estelle and Oscar’s cousin, Princess Leonore, the oldest child of Princess Madeleine and Christopher O’Neill, celebrated her 6th birthday in Miami, where the family relocated in the fall of 2018.

RELATED: Swedish Royal Family Gives Rare Glimpse Into Princess Estelle and Prince Oscar’s Start to Summer

Prince Oscar and Princess Estelle | Linda Broström / Courtesy Royal Court
Prince Oscar and Princess Estelle | Linda Broström / Courtesy Royal Court

Can’t get enough of PEOPLE‘s Royals coverage? Sign up for our free Royals newsletter to get the latest updates on Kate Middleton, Meghan Markle and more!

In October, King Carl XVI Gustaf announced his decision to have some of his grandchildren’s royal titles stripped. The palace announced that the children of Princess Madeleine and Chris O’Neill, as well as Prince Carl Philip and Princess Sofia, are no longer official members of the royal house, which means they are no longer expected to perform official royal duties.