Abu Qataadah Radiyallahu 'Anhu reports that Rasulullah Sallallahu 'Alayhi Wasallam said:
"Whomsoever sees me, that is, in a dream, has seen that which is a fact". (RU)
App reference (RU): Book 56, Hadith 7 (RU)
English reference (RU): Book 55, Hadith 394 (RU)
Arabic reference (RU): Book 56, Hadith 412 (RU)