Sunan Ibn Majah, Volume 2, Book 5, Hadith 1145 (DarusSalam) ⓘ
It was narrated from Hafsah bint ‘Umar that when the call for the Subh prayer was given, the Messenger of Allah would pray two short Rak’ah before going to the prayer.
حَدَّثَنَا مُحَمَّدُ بْنُ رُمْحٍ، أَنْبَأَنَا اللَّيْثُ بْنُ سَعْدٍ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، عَنْ حَفْصَةَ بِنْتِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ كَانَ إِذَا نُودِيَ لِصَلاَةِ الصُّبْحِ رَكَعَ رَكْعَتَيْنِ خَفِيفَتَيْنِ قَبْلَ أَنْ يَقُومَ إِلَى الصَّلاَةِ .
also referenced under: Hadith 1145 (Reference) & Book 5, Hadith 1199 (In-Book)