It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with him) that the Prophet (peace and blessings be upon him), Usamah bin Zayd, Uthman bin Talhah and Bilal entered the Ka'bah. He (peace and blessings be upon him) stayed in it for a long time, and I was the first to enter after the Messenger of Allah (peace and blessings be upon him). I asked Bilal (may Allah be pleased with him): Where did the Messenger of Allah (peace and blessings be upon him) pray? He said: "Two rak'ahs between the two front pillars."
Hadith Referenceالمعجم الكبير للطبراني / باب الباء / 1047