"When midnight came and everyone in the palace was sound asleep, the nurse who alone watched by the baby’s cradle in the nursery saw the door open gently, and who should come in but the real Queen. She lifted the child from its cradle, laid it on her arm, and nursed it for some time. Then she carefully shook up the pillows of the little bed, laid the baby down and tucked the coverlet in all round him. She did not forget the little Roe either, but went to the corner where it lay, and gently stroked its back. Then she silently left the room, and next morning when the nurse asked the sentries if they had seen any one go into the castle that night, they all said, “No, we saw no one at all."
“Brother and Sister” by the Brothers Grimm (read it here)