It looks like Zac Efron is off the market! The "High School Musical" alum is sparking some serious romance speculation with Vanessa Valladares after the two were spotted out and about together holding hands in Australia. "Zac met Ness earlier in the summer. They started hanging out in July and recently took a ski trip together," the source told PEOPLE. "You can tell that they are having fun. She spends a lot of time at this house." Here's what you need to know about the 25-year-old model.