Efron, 28, who has been abroad with Miro since last week, debuted the new look while in Kyoto, the one-time capital of Japan.
In a series of photos shared on Instagram, the star explored what looked like a traditional Japanese wooden house - one of many in Kyoto, which is also home to many classical Buddhist temples.
The star's mustache took center stage in one photo, where he flashed the peace sign. Efron accompanied the image with a Japanese flag emoji, followed by the characters for "I Love You."