The striker is currently away on World Cup duty with Belgium following a memorable first campaign at Old Trafford, and scored twice in his country's 3-0 win over Panama in their opener on Monday.
Lukaku will be hoping to progress deep into the tournament in Russia, which would mean he would miss the Reds' pre-season return to the States next month.
But he recalled last summer's trip fondly during an interview with ManUtd.com before he departed to link up with Belgium.
When asked what was the most enjoyable thing about the 2017 tour, Lukaku declared: “Oh, man – everything, mainly because it was my first one.