Zac Efron has a lot of respect for his fellow Hollywood star Leonardo DiCaprio. On Thursday, the Baywatch actor gave a sweet shout-out to the Oscar winner and self-proclaimed environmental activist on Instagram. "RESPECT to @leonardodicaprio for his tireless work fighting for our environment #🙌🏼🙌🏼🙌🏼 #LDF #InstagramKindnessDay #TBT," he captioned a throwback photo of the two at an LA Lakers game in November 2008. In the snap, Zac is sporting his old shaggy haircut from his High School Musical days. Oh my, how things have changed. We certainly wouldn't mind seeing this friendship strike up again.