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". (TR)
App reference (TR): Book 56, Hadith 7 (TR)
English reference (TR): Book 55, Hadith 394 (TR)
Arabic reference (TR): Book 56, Hadith 412 (TR)