It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that the Noble Prophet (peace and blessings be upon him) assumed Ihram after the (Dhuhr) prayer.
Hadith Referenceسنن دارمي / من كتاب المناسك / 1844
Sayyiduna Anas bin Malik (may Allah be pleased with him) narrated that the Noble Prophet (peace and blessings be upon him) entered into the state of Ihram and recited the Talbiyah after the prayer.
Hadith Referenceسنن دارمي / من كتاب المناسك / 1845