Watford have reportedly been tracking the development of Jordan Lukaku over recent months.
The 21-year-old, who is the younger brother of Everton striker Romelu, has featured on a regular basis for Belgian side KV Oostende this season.
According to ESPN, his performances have captured the attention of the Hornets.
It is believed that Watford will be in the market for a new left-back this summer, with loanee defender Nathan Ake due to return to his parent club Chelsea.
The younger Lukaku sibling has been tipped to be included in the Belgium squad for Euro 2016, having earned two senior caps to date.
