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