Gilbert, 38, announced his decision on-air on Vivacité, a Belgian radio station, during Sunday's Amstel Gold men's race.
"Yes," he said answering a question about 2022 being his last year. "That's why sometimes it's difficult to say that you have to miss races like today's. These are races that are close to my heart. I would have been very happy to be at the start."
The Belgian star of the sport is one monument short - Milan San Remo - of completing a rare sweep of the five big one-day races of the sport. In addition to those successes, he was the world road race champion in 2012 and has built a reputation as one of the best cyclists of his generation.
"At some point I have to stop," he said. "It will be 20 years of my career. You have to think that cycling is not the only thing in life. There is also my family. I have sacrificed a lot in my life and it's time to enjoy it."
Gilbert was on a break after competing at Gent-Wevelgem, citing physical and mental fatigue after rehabilitation from a fractured kneecap sustained at last year's Tour de France. He has said that he'll return for Fleche Wallonne on Wednesday, a race that he won back in 2011, but is uncertain of his current form after returning from his broken knee and now fatigue.
"I had a lot of pain and it was hard to get back," said Gilbert. "I paid for all those kilometres where I kept riding with a huge pain in my knee. I had a large pain load for many months and my body said stop. The decision I made with my team to take this micro-break was the right one. I hope to come back with better sensations.
"I took a few days of complete rest and then I did some rides of more than six hours to improve my endurance. Physically, I won't be too bad, but I am aware that I will miss some preparatory races like the Basque Country. It is a race that helps a lot.
"I will start without any clear ambition, but first of all with the idea of having fun and going as far as possible. Perhaps racing without pressure will give me a certain freedom. I hope that I will still be there in the final of these two beautiful Classics."
Gilbert will get back to racing on Wednesday for Flèche, a race which he has won on one occasion – back in 2011 – before continuing at Liège-Bastogne-Liège, where he completed a famous Ardennes triple in the same year.
SBS VICELAND and SBS On Demand will be the place to watch Fleche Wallonne, with the women's race coverage starting from 1905 AEST and the men's race broadcast beginning at 2100 AEST.