They were first rumored to be dating back in February 2012 when they were spotted holding hands during a friend's birthday dinner at L.A. eatery STK. The broke up later that May because of their busy schedules.
Spotted going to the movies together in October 2013 following Efron's stint in rehab for cocaine addiction.
Zac said he was single in January 2014.
*The relationship was never confirmed & is therefore a rumor.