The Belgian left the Blues after one season back at Stamford Bridge to sign for Inter Milan on loan.
Lukaku enjoyed a strong start to his Chelsea comeback but his form deteriorated and he fell out with then-boss Thomas Tuchel.
He scored 14 goals for Inter last term and returned to Chelsea in the summer only to be loaned out again, this time to Roma.
His future in west London is still incredibly uncertain, and his relationship with the fans remains on the rocks following his December 2021 interview when he said he wanted to return to Inter.
Lukaku has now come out and said that he might have 'exploded' during his departure last summer.
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Speaking after a press conference with the Belgian national team via Sportitalia, he said: "Most of the people here in the room know me. I don't like beating around the bush.
"I'll speak in time, but if I actually said how last summer went, everyone would be shocked.
"There were times when I really thought I might explode, five years ago I probably wouldn't have stood back and done it.
"Now I am focused on what I do best, I know how to play football. I worked hard all summer. I also have to thank Radja Nainggolan for giving me the contact with Roma."
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Since signing for Roma in the summer, Lukaku has rediscovered the form that made him one of Europe's best strikers.
He has scored seven goals in eight appearances for the club, playing under the management of Jose Mourinho once again.
Lukaku's contract at Chelsea isn't due to expire until 2026, with next summer set to raise speculation over a move yet again.
A return to the Blues side looks unlikely though, with the striker clearly shining in Serie A.