The lovebirds and co-stars were supposed to be in London for the screening on Tuesday (20Apr10), but when all planes to and from Europe were grounded last week (15Apr10) following the volcano eruption, their plans were scrapped.
Cyrus was upset when she learned she would be unable to fly to the U.K., but her family made her realise it was a good thing.
Speaking via satellite on Britain's Live From Studio Five TV show, she says, "I was kind of freaking out about how I was going to make up all of the things that I was supposed to do. I was especially bummed just about the premiere that I couldn't go to; that was the thing that made me the most sad.
"Me and my family were joking around; they were like, 'Miley you're such a freak about working and working all the time that the only thing that can stop you from going to do more work is a volcano'. They were like, 'That's really sad... that's the only way we can get you to spend any time with us is a volcano?'
"It was pretty crazy when I heard that the trip was getting cancelled, because of course I was stressing out about packing... As soon as I finished packing all of my stuff, which is very hard when you're going away for a while to a completely different country... I got the text, 'You're not going any more'. I was like 'Oh, great'."