Sayyiduna Ibn Umar (may Allah be pleased with them both) said: The Messenger of Allah (peace and blessings be upon him) entered the House of Allah, and with him (peace and blessings be upon him) also entered Sayyiduna al-Fadl bin Abbas, Sayyiduna Usamah bin Zayd, Sayyiduna Bilal and Sayyiduna Uthman bin Talhah (may Allah be pleased with them). He stayed for a long time, then came out. I went ahead of the people and was among the first to enter, and I met Bilal (may Allah be pleased with him). I asked: Where did the Messenger of Allah (peace and blessings be upon him) pray? He said: "Between the two front pillars." Ibn Umar (may Allah be pleased with them both) said: "And I forgot to ask how many rak'ahs he prayed."
Hadith Referenceالمعجم الكبير للطبراني / باب الباء / 1050