It is narrated from Hazrat Aisha that when the Prophet (peace be upon him) wished to sleep in a state requiring ghusl, he would perform ablution as for prayer, and when he wished to eat or drink, he would wash his hands and then eat or drink.
Hadith Referenceمسند احمد / مسند النساء / 24714
Hadith Gradingحکم دارالسلام:حديث صحيح، صالح بن أبى الأخضر ضعيف، ولكن توبع، أنظر: 24872