Our kids are getting up earlier and earlier each morning. If it isn't one, it's the other. With a single baby, at an appropriate age, you can ignore it so it learns to sooth itself back to sleep. Unfortunately, with twins (or two siblings sharing a room) it isn't fair to the sleeping child.
Yesterday Natasha got up just before 5* and I got up to get her. I rocked her for a little bit but that wasn't enough so I made her a bottle. Unfortunately she was already up for the day and her brother soon followed.
Today I thought I was smarter and went right to the bottle. It worked and she went back to sleep. Unfortunately, brother woke up when I wasn't in the room and he woke up up too. It was a rough morning.
(*) this is working off sleep deprived memories so it could have been a different night and the time might be slightly different.