Sayyidah Maymunah (may Allah be pleased with her) said: I placed water for the Prophet (peace and blessings be upon him), then I hung a screen for him (peace and blessings be upon him) until he (peace and blessings be upon him) had completed the ritual bath.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 953