The circuit activated its clause due to the increase cost of hosting the race, casting a doubt over the Grand Prix's future which has been on the F1 calendar every year.
2020 could see two new venues enter the calendar in F1, with Vietnam already confirmed for an April slot.
Commenting on bringing the famous race series to Vietnam Hanoi chairman Nguyen Duc Chung said: "It demonstrates Vietnam's ability, as one of the fastest growing economies in the world to host events on a global scale and attract tourism to the country".
"Silverstone was the first grand prix, but we haven't raced at Silverstone all those 68 years".More news: Nicole Kidman Opens Up About Her Scientologist Kids In Rare Interview!
Earlier this week F1's commercial managing director Sean Bratches hinted that the race could move away from Silverstone, its permanent home since 1987 and a regular F1 venue throughout the championship's history.
"It's hard to explain why it has been tough for us, particularly in this last one, but I really hope the vehicle this weekend feels more normal and we are more competitive".
Bratches said the sport valued and wanted to keep the "heritage races" - such as Silverstone, Spa and Monza - and recognised their importance to fans.More news: Pat Howard pushed out early as Cricket Australia purge continues
"We plan for this to be a long-term agreement, and we intend for this to be a long-term partnership", he added. "Firstly, we want to preserve the heritage races. I think that if you are not in Ferrari or Mercedes, winning the world title is a bit hard", he told Efe news here.
It originally looked like the proposed Miami street race would have that honour. Vietnam's concept of what grand prix racing should be about matches our vision for the sport.
"Most of our grands prix are now half an hour to an hour outside cities, so this race in Hanoi fulfils one of our preliminary goals - an iconic city hosting racing on a potentially thrilling street circuit". I don't think we want to provide a lot of "inside the tent" commentary on active discussions. "We have Monaco, Baku and Singapore, and this is a great addition to that lineup".More news: Ranveer Singh, Deepika Padukone head to Italy for their wedding