Japanese baseball player Shohei Ohtani joined the Los Angeles Dodgers in December (Frederic J. Brown)

Japanese baseball superstar Shohei Ohtani revealed on Thursday that he is now married but kept the identity of his wife a mystery.

The Los Angeles Dodgers player said he was beginning not only "a new chapter in my career with the Dodgers but I also... began a new life with someone from my native country of Japan who is very special to me and I wanted everyone to know I am now married".

"I am excited for what is (to) come and thank you for your support," the 29-year-old said in an Instagram post that racked up almost 1.5 million likes in just one hour.

Ohtani, who won his second American League Most Valuable Player award in six seasons with the Los Angeles Angels last year, included a picture of his dog at the bottom of the post.

"The two of us (and our dog) will support each other and we hope to move forward together with all of our fans," he also wrote in Japanese.

He added that he and his wife were "still immature in many ways, but we would appreciate your kind support".

Ohtani, nicknamed "Sho-Time", has achieved stratospheric fame in Japan and abroad.

Known for his skills as a pitcher as well as a batter, he helped Japan win last year's World Baseball Classic.