The Chelsea striker revealed in a conversation with Sky Italia that he was not happy with the situation at the club and hinted that he had problems with manager Thomas Tuchel's style of play.
Lukaku has now apologised for his comments and is in the squad as the Blues prepare to take on Tottenham in the first leg of the League Cup semi-final tonight (05.01.22).
In an interview with Chelsea's club website, Lukaku said: "To the fans, I'm sorry for the upset that I caused.
"You guys know the connection that I have with this club since my teenage years, so I totally understand you guys being upset.
"Obviously, it's up to me now to restore your trust and I'll do my best to show commitment every day on the training ground and in the games, trying to make sure that we win games.
"And also to the manager, I apologise, and also to my team-mates and the board, because I think it was not the right moment also and I want to move forward from this and make sure that we start winning football games and that I perform for the team in the best manner."
Lukaku was dropped for the draw against Liverpool at the weekend but Tuchel says that both the club and the player now want to move on from the issue.
The German coach said: "He has apologised and is back in the squad for today's training [session] later.
"We have had enough time to clear the air and move on.
"For me, the most important thing was to understand and clearly understand and believe that it was not intentional.
"He did not do this intentionally to create noise in front of such a big game."