Leah Isadora Behn, daughter of Princess Märtha Louise of Norway, marked her first birthday without father Ari Behn, but she had the support of her mother on the "bittersweet" day.

It's been a tough few months for Princess Märtha Louise and her three daughters- Maud Angelica Behn, Leah Isadora Behn, and Emma Tallulah Behn, since the death of Märtha's ex-husband Ari Behn, who committed suicide on the Christmas Day last year. Leah Isadora Behn's 15th birthday is her first since her father tragically took his own life, and also the first occasion of celebration in the family, reports Hello.

Märtha Louise took to Instagram to wish her daughter on her birthday, sharing four pictures of the young girl throughout the years, and noted that it was a "bittersweet" moment for them.

Showering her daughter with praises, the 48-years-old wrote: "Happy 15th Birthday, my wonderful Leah. You are an amazing young woman with so many talents; you are funny, kind, beautiful and graceful with a smart head on your shoulders."

The Norwegian royal revealed that Leah is the most organised person in their family, for which Märtha is "eternally grateful." She also gushed that Leah has inherited the "gift of art" from her father Ari Behn, an author, and said the art "expresses itself through beautiful makeup IG posts."

"And although this day is bittersweet in more ways than one, you make the best of it and stay true to your emotions," Märtha said of her daughter, adding that the little one inspires her every day.

"I am so proud of you. Love you with all my heart," she concluded. Märtha's boyfriend Shaman Durek also posted a message for Leah in a comment on the Instagram post and called her a "beautiful bright light."

prince magnus
(L-R) Leah Isadora Behn, Princess Ingrid Alexandra, Prince Sverre Magnus, Maud Angelica Behn, Queen Sonja, Emma Tallulah Behn, King Harald, Crown Princess Mette-Marit, Crown Prince Haakon and Martha greet wellwishers from the balcony of the Royal Palace in Oslo, Norway on May 9, 2017 HAAKON MOSVOLD LARSEN/AFP/Getty Images

"I'm so happy Leah you like my gift. I miss you so much and all the laughter and tik tok fun. I love you all and mom. There isn't a day that goes by that your not on my mind. Happy Birthday darling," the celebrity shaman said.