Roma are yet to make their official announcement but Serie A have confirmed that the deal is done on their list of completed transfers.
Thousands of fans greeted Belgium striker Lukaku after he touched down at Ciampino airport just outside the Italian capital on Tuesday, his arrival a boost for Roma following a worrying start to the new Serie A season.
Italian media report that Chelsea accepted Roma's offer of around six million euros (£5.15 million) to take outcast Lukaku for this season, giving the Italians the striker they have been looking for since Tammy Abraham damaged knee ligaments at the end of last season.
Lukaku has agreed to take a pay cut from nearly 11 million euros (£9.5 million) to around 7.5 million euros (£6.5 million) in order to move to Roma, who are operating under a Financial Fair Play settlement agreement made with UEFA.
Roma have collected one point from their first two matches and their inability to convert dominance into goals was fully on display during Saturday's 2-1 loss at Verona.
Chelsea meanwhile have been trying to permanently offload Lukaku all summer in a bid to end a disastrous transfer that cost the Premier League club a 115 million euro (£98.8 million) purchase fee from Inter Milan and his whopping annual salary.
But talks with Inter - where he was loaned back to last season - collapsed reportedly after the club discovered he had been secretly talking to their biggest rivals Juve and AC Milan.
Instead, he has been reunited with his former coach at Manchester United Jose Mourinho as the capital club try to qualify for the Champions League for the first time since 2018.
