´It was narrated from Ibn 'Umar that Hafsah told him:` "When he was called to Subh prayer, the Messenger of Allah (ﷺ) would do two prostrations before Subh prayer."
Hadith ReferenceSunan an-Nasa'i / The Book of Qiyam Al-Lail (The Night Prayer) and Voluntary Prayers During the Day / Hadith: 1772