The Blues winger has made the move to Stamford Bridge after being signed in January.
But the USA international was loaned back to Borussia Dortmund for the remainder of the season.
And now his former team-mate and Arsenal superstar Aubameyang has wished Pulisic good luck at his new club.
He posted: “My bro welcome to the @premierleague I know you gonna smash it you always showed me respect so I wish you all the best @cpulisic_10”.
Pulisic opened up on his relationship with Aubameyang yesterday and revealed he had asked for some advice from the striker before opting to join Chelsea.
“When the possibility of my transfer to Chelsea came around, I reached out to him,” he explained to the Evening Standard.
“Even though Pierre-Emerick left Dortmund for Arsenal, we remained in contact.
“I have spoken with him on and off ever since he moved here.
“I asked him how it was in London and stuff. He loves it here.
“He is a big city kind of guy, you can see that and he has told me about a few places to go see.”
Pulisic has also revealed banter between himself and Aubameyang ahead of Chelsea taking on Arsenal in the Europa League final.
“We have bantered about that already,” he revealed.
“I have told him ‘you can score one goal in the Europa League Final, but you can’t win. That’s it!’
“I knew that he’d do well in this country. He did it in the Bundesliga. He is just a guy that will always score goals. He will work hard and find that right spot. He is what a great striker can do.
“Does seeing how well he has done in the Premier League give me the confidence I can do the same? Yes, absolutely.
“It’s going to be great for me because I will always have a guy like him to take advice from and to learn from.
“It’s great to still have that relationship even though we are not going to be friends when we play against each other.”
Chelsea take on Arsenal in the Europa League final next Wednesday in Baku, Azerbaijan (8pm).