Oscar II of Sweden
Oscar II , baptised Oscar Fredrik, was King of Sweden from 1872 until his death and King of Norway from 1872 until 1905. The third son of King Oscar I of Sweden and Josephine of Leuchtenberg, he was a descendant of Gustav I of Sweden through his mother.
Oscar II never officially recognized any illegitimate children of his. He is also alleged to have had two sons with the actress Marie Friberg, Nils and August Ekstam .
Source: Wikipedia