The actor - who plays a war-weary romantic in The Lucky One - told Flicks and Bits that he hit it off with Schilling from their very first meeting.
"It was weird, it was a screen test I think. You kind of get thrown into it, and either you click or you don't," Efron recalled. "I'm pretty sure you know right away; thankfully we clicked right away. It was instant. We were hitting our stride almost immediately."
Efron went on to admit that Schilling actually taught him a great deal about acting.
"I found that I learnt a lot from her, which is always refreshing... it's a refreshing quality to see in your leading lady, it's fun," he said. "She's hilarious but she's very focused when it comes to the work. I was blown away by her."
Schilling recently described starring in The Lucky One as a huge journey.
The Lucky One opens on April 20 in US cinemas and in the UK on May 2.
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Watch a trailer for The Lucky One below: