Jose Mourinho is reportedly keen to bolster his ranks at Stamford Bridge ahead of the second half of the season, with midfield said to be an area he deems a priority.
And Guarin's representative Marcelo Ferreyra has revealed that the Colombia international is Mourinho's prime target, while there is also interest from both Manchester United and Manchester City.
"The interest of Chelsea is virtually official," he told Radio Caracol.
"Fredy is happy at Inter and we will have to carefully evaluate the London club's project for the future.
"The two Manchester clubs have also shown an interest, but he is a back-up for both of them.
"There have been a number of contacts between the Nerazzuri and Chelsea officials. We are all waiting for a decision from (Inter) president Erick Thohir."
Colombia international Guarin has started all 16 of Inter's Serie A fixtures this season, scoring three goals.
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