The pair played together on-loan at Everton last season.
"I think Lukaku is a really great footballer - he helped Everton last year very much indeed," Deulofeu said.
"He has huge quality and I think he will do very well at Everton this season.
"The only thing I can say is that I wish the best for him - I am happy for him to go to Everton because he is going to have a great season, which will help him a lot."
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