Keisse, a Six Day specialist, has triumphed at the Gent event on six previous occasions, while Viviani is the reigning Olympic Omnium champion after winning gold in Rio at the 2016 Summer Games. The Belgian and Italian riders will race in Deceuninck-Quick-Step jerseys after it was announced that Deceuninck would become co-title sponsors of the Belgian WorldTour team from the start of the 2019 season.
"The Six Days of Gent is always a special event for me, one to which I look forward every year," Keisse, 35, said in a release issued by his team. "I'm happy to be back on the bike and ride with Elia, an Olympic Champion on the track and the most successful rider of 2018 on the road. My family will be there, the fans will come in huge numbers and create a fantastic atmosphere and we'll do our best to get the victory, especially as it's been a few years since the last time I won here."
Viviani has raced the Gent Six for the last two years and used the event as part of his build up to the road season. He raced in 2017 with fellow Italian Michele Scartezzini, but paired up with Keisse in 2016.
The Italian only joined Quick-Step Floors at the start of this season but enjoyed his best year to date. He won a stage at the Tour Down Under in January and never looked back, winning the GC and two stages at the Dubai Tour, a stage at the Abu Dhabi Tour, four stages and the points jersey at the Giro d'Italia, the national road title and three stages at the Vuelta a Espana.
"I'm excited to be going to Gent and riding with Iljo. I'm sure it will be an amazing week, but also a difficult one, because many teams will be aiming for the win. To triumph in such an event you have to be both strong and smart. We are motivated for this, we hope to put on quite the show for all the fans in the stands and to take the overall victory in the mythical Kuipke," said Viviani.