Marciello and Engel will be joined in the event on the bill of the Formula 3 Macau Grand Prix on 18/19 November by Daniel Juncadella and Jules Gounon.
It will be the first running of the World Cup on the Guia street circuit in the Chinese territory since 2019.
The event, which was inaugurated in 2015, has not taken place since as a result of the COVID pandemic and travel restrictions in China.
Marciello, who won the last edition of the World Cup, will race a Mercedes-AMG GT3 for the Landgraf team with which he took the ADAC GT Masters title last year.
Inaugural World Cup winner Maro Engel again drives for Craft-Bamboo, the team with which he took victory in the Macau GT Cup last year.
It was the German’s third victory on the 3.8-mile Guia track: he also won the GT race in 2014, the year before it gained FIA world status.
Juncadella, who won the F3 Grand Prix in 2011 aboard a Mercedes-powered Dallara, will race a second Merc run by Craft-Bamboo, which won the GT World Challenge Asia title this year.
Macau rookie Gounon will take part with the Chinese Climax Racing team, which also competes in the GTWC in Asia.
Mercedes is going into the event as the most successful manufacturer in its history: it has won three of the five editions of the World Cup so far and is also on a four-year winning streak in the GT event.
Head of Mercedes-AMG customer racing Stefan Wendl said: “We will send our most successful drivers this season, who also have heritage in Macau except for Jules who will be our rookie.
“After winning with Lello [Marciello] in 2019 we have been a few years on pause with the World Cup, but at least last year Lello and Maro attended the race and we won it also.
“We have something to loose and we are going there to win it again. That is clearly the target, knowing that the competition will be very tough.
“They will all try to beat us and that is why we will send out the best drivers.”
A total of six Mercedes-AMG GT3s have been entered for the World Cup. Climax has a second car for a driver who has yet to be nominated, while Marchy Lee will race a Merc for Toro Racing.
The FIA GT World Cup will awarded at the end of a one-hour race ahead of the F3 race on Sunday, 19 November.
The grid for the main race will be decided by a one-hour qualifying race on the Saturday.
The full entry list for the 70th anniversary Macau event is scheduled to be announced on Wednesday.
