Abu Nasr (may Allah have mercy on him) said: I entered ihram for Hajj, then I caught up with Sayyiduna Ali (may Allah be pleased with him) and asked: I have entered ihram with the intention of Hajj; may I add an Umrah to it? He said: No! Had you entered ihram for Umrah and then wished to add Hajj to it, you could have done so; but since you began with Hajj, do not add Umrah to it. I asked: Then what should I do if I wish to perform both? He said: Pour a vessel of water over yourself, then enter ihram for both together, and perform two tawafs.
This Abu Nasr is not known.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 8748