Actor Ryan Merriman proposed to longtime girlfriend Kristen McMullen over New Year's Eve and managed to keep the big news a secret until now.

During the premiere of Jackie Robinson biopic 42 in Hollywood on Tuesday night, the Pretty Little Liars star confirmed the news and explained how the couple's "hectic" engagement night in his native New Zealand turned out perfect.

"There is this awesome thing called Sky City, with a Stratosphere tower, and they light off about $300,000 worth of fireworks at midnight," he tells Us Weekly magazine. "As soon as I gave her a kiss and proposed, the fireworks started going off. It was kind of like a movie."

But the couple's evening didn't turn out that smooth, Merriman says their hunt for a great New Year's Eve hangout nearly ended in disaster.

"We started out at this terrible bar. It was supposed to be tiki torches and beautiful, but it was not at all," he explains. "There was a terrible DJ. [It] ruined the whole night."

The couple then tried another club, but it turned out to be much too loud and Merriman says if he did it there he would "regret it for the rest of his life."

"So we ended up running to Sky City, the harbor...I did it on the fly of the moment," he reveals. "Thank God it worked."

The couple has yet to set a date.