Some clues:
He played a character on Grey's Anatomy and then died and became a ghost.
He played a character on Supernatural and then died and became a ghost.
It's Sir! Jeffrey Dean Morgan aka Denny aka Papa Winchester aka Negan!!
And his first tweet was with his TV sons:
First twit. My boys!! @JensenAckles@jarpad#minncon#spnfamily#boccepic.twitter.com/ffCBCqxpSa
— Jeffrey Dean Morgan (@JDMorgan) August 14, 2016
Also, his bromance with Norman Reedus remains strong.
Hey pal. Thinking of ya along with some friends. @wwwbigbaldhead#minncon#spnfamily@TWDFamilyy@twd_fan_pagepic.twitter.com/FpFHkfKsJV
— Jeffrey Dean Morgan (@JDMorgan) August 14, 2016
ONTD, are you ready to accept JDM as your lord?
Source 1, 2