It was narrated from Anas:

That the Messenger of Allah prayed Zuhr in Al-Baida', then he mounted and rode up the mountain of Al-Baida', and he began the Talbiyah for Hajj and 'Umar when he had prayed Zuhr.

أَخْبَرَنَا إِسْحَاقُ بْنُ إِبْرَاهِيمَ، أَنْبَأَنَا النَّضْرُ، قَالَ حَدَّثَنَا أَشْعَثُ، عَنِ الْحَسَنِ، عَنْ أَنَسٍ، أَنَّ رَسُولَ اللَّهِ ﷺ صَلَّى الظُّهْرَ بِالْبَيْدَاءِ ثُمَّ رَكِبَ وَصَعِدَ جَبَلَ الْبَيْدَاءِ وَأَهَلَّ بِالْحَجِّ وَالْعُمْرَةِ حِينَ صَلَّى الظُّهْرَ .