Credit: Steve Granitz/

Miley Cyrus and her Aussie beau Liam Hemsworth made their red carpet debut Thursday at the Los Angeles premiere of their new Nicholas Sparks drama The Last Song.

"We had a lot of fun! It was pretty much jokes every day!" Hemsworth, 20, told of shooting the flick with Cyrus, 17. "Jokes and shooting on the beach -- there wasn’t much to complain about!"

Cyrus told Us the most challenging part of being on the red carpet wasn't stepping out with her beau for the first time.

It was "knowing that beauty is pain and wearing the highest heels possible!" she joked to Us.

Asked who designed her dress, she told Us, "I have no idea who made this thing, but I love it. My stylist just made me throw it on!"

After months of public PDA, Cyrus confirmed for the first time that she and Hemsworth were an item at this year's Academy Awards.

In the new Us Weekly (on newsstands now), she recalls meeting him for the first time.

"I got a little bit nervous about how tall he was [she’s 5-foot-5; he’s 6-foot-5]," she tells Us. "I thought I might have to stand on apple boxes to film! But he opened a door for me, and I thought it was very sweet. So I just told them, 'He's got the part!'"