The 28-year-old Belgium hitman, who has returned to Stamford Bridge in a £98million deal from Inter Milan, was initially handed the number 18 jersey, but jumped at the chance to take the squad number following Tammy Abraham's £34million exit to Roma, which left the he main striker's shirt vacant.
And the former Everton and Manchester United forward is excited to become the focal point of the Blues' attack and show his leadership qualities.
"I have the number nine shirt, I'm very happy and very fortunate to be in the situation," Lukaku said. "Cesar Azpilicueta's the captain, he's been here for many years, he's a great captain. When I was in quarantine he was already messaging me, to help about houses and things like that.
"So in terms of leaders, there are many players that have big personalities in this dressing room.
"I'm one of the players who likes to connect everybody, and make everyone feel comfortable and give them confidence, because those players deserve to be Chelsea players and they showed that last season.
"So this dressing room has a lot of personality, which I like.
"It's good to be back. As a footballer, you fight to achieve your dreams. I'm here now and I can't wait to get on the pitch and perform with my team-mates."
Champions League winners Chelsea started the campaign with a commanding 3-0 win over Crystal Palace, and will head to Arsenal on Sunday with confidence.
Lukaku's arrival will put another spring in the step of Thomas Tuchel's team, with the marksman confirming he is fit and ready to go at the weekend.
Belgium's record goal-scorer spent three years at Stamford Bridge between 2011 and 2014, and has already admitted to some unfinished business on his return to west London as a senior professional.
"The dream is reality, so I just have to prove it now,” Lukaku said. "I already have a relationship with most of the players. I'm really happy to be here, and now we've got to play as a team.
"The guys are very hungry to keep winning, and training (on Tuesday) had a good intensity. Everyone wants to keep improving,” the new number nine said.