Peter Facinelli says the weather almost ruined his romantic proposal.

Peter Facinelli

Peter Facinelli

The 'Twilight' star, who recently got engaged to 'Thor' actress Jaimie Alexander, hired a plane to fly a banner asking her to marry him while they were on top of the Empire State Building in New York at 4PM on March 16, but admits it was difficult to convince her to stay outside because it was so cold.

The 41-year-old actor said "At 3:55 she was like, 'I'm cold, I'm going to go inside.' And then all of a sudden I look up when she went in and the plane was there!"

Peter eventually got the brunette beauty to go back outside, but was worried he had missed his opportunity.

He told PEOPLE.com: "I had binoculars and I looked up and I saw a helicopter, and I looked and couldn't find [the plane] because I was nervous that it had left, and then I gave the binoculars to her and she goes, 'Yeah, it's right there,' and then she read the banner, so it worked out."

The actor, who has three daughters Luca, 17, Lola, 12, and Fiona, eight, with ex-wife Jennie Garth, then struggled to get down on bended knee.

He explained: "I had just bought these new jeans and they were a little tight, so I said, 'My jeans are tight but I'll try to get down on one knee.' "

The couple - who met when they worked on the romantic-comedy the 'Loosies' - were first romantically linked in November 2012.