Jose Mourinho has made the club's intention to sign Rooney clear this summer, while the Belgian is also part of the Stamford Bridge boss' plans for this season after a successful loan spell with West Brom.
And Lukaku is already relishing the potential challenge of more competition for places in the form of the Manchester United striker next season.
|14/1||Wayne Rooney is 14/1 with Paddy Power to be the Premier League top goalscorer
"I like competition. Obviously, if he does sign, it could be a good partnership but it is the manager's choice.
"You have to accept that you have to work hard to make it a successful squad. If he is part of our team I will welcome him with open arms."
Lukaku, meanwhile, has been impressed by Mourinho's approach as he works with the former Real Madrid coach for the first time.
He added: "He is a great manager. He is very direct - and I love that. If he has something to say to you, he says it. That is a good thing.
"I would not say he has given me a hard time but he is very direct and in your face. I have had to work more than I ever have but I like to work."