The 2016 gold medallist from Rio returns to the White Rose county with BMC Racing, having finished seventh overall in the first staging of the race in 2015.
Since then he has gone on to become one of the biggest names in road cycling, with the Olympic title one of many he has racked up, including two Tour de France stages, the 2017 Paris-Roubaix title.
The news comes just days after Team Dimension Data confirmed sprint king Mark Cavendish would be fit to start the race, which begins in Beverley on Thursday, May 3.
Welcome to Yorkshire chief executive Sir Gary Verity said: “It’s fantastic news that Greg will be competing and he is sure to receive a very warm welcome.
“He is one of the most exciting, classy and respected riders in the sport and will no-doubt animate the four days of racing. The final stage should certainly suit him and I look forward to seeing him in action.
“The word has definitely got around the peloton that the Tour de Yorkshire offers huge crowds and exciting racing, and having riders of Greg’s calibre in attendance will be a huge draw to the millions of spectators we’re expecting to line the race route.”
Van Avermaet’s Belgian compatriot – and defending Tour de Yorkshire champion – Serge Pauwels is another big-name rider to have confirmed his attendance, with more top professionals expected to be unveiled in the coming days.