The 2020 Davis Cup Finals have been rescheduled for 2021, as have the Fed Cup Finals, due to the ongoing COVID-19 pandemic.
The Fed Cup Finals were due to take place in April of this year and had already been postponed.
Initially scheduled for November 23 to 29 2020, the Davis Cup Finals have now been formally postponed and are due to start on the week commencing November 22 2021 instead.
The 18 teams qualified for the 2020 finals will remain the same.
All 24 World Group I and World Group II ties due to take place in September have also been deferred to 2021.
The International Tennis Federation (ITF) and investment group Kosmos Tennis made the announcement following a three-month review of the logistical and regulatory challenges that have arisen since the start of the pandemic.
The Davis Cup is the largest men's team competition in tennis, with Spain the defending champions.
This year's edition was the first using a new format.
Spain and Barcelona footballer Gerard Piqué, President of Kosmos Tennis, commented: "It's a huge disappointment for all of us that the Davis Cup Finals will not be held in 2020.
"We don't know how the situation will develop in each qualified nation, or if restrictions in Spain will remain sufficiently eased, as such it is impossible to predict the situation in November and guarantee the safety of those travelling to Madrid.
"This postponement has no long-term bearing on our collective ambitions for the Davis Cup."
ITF President David Haggerty added: "This is a tough decision to have to make, but delivering an international team event on this scale while guaranteeing the health and safety of all involved ultimately poses too great a risk.
"It is a complex undertaking and we have made the decision now to provide certainty for players, National Associations and fans.
"We look forward to continuing our partnership with Kosmos Tennis in order to deliver a fantastic competition next year."
Meanwhile, the Fed Cup Finals have been given new dates of April 13 to 18 next year.
They remain at the László Papp Arena in Hungarian capital Budapest, set to be played on an indoor clay court.
Twelve nations - including hosts Hungary, reigning champions France, the United States and Australia - will compete for the title, with the draw remaining the same.
Four regional events still to be played - two in Americas Group II and one each from Asia-Oceania Group II and Europe-Africa Group III - will now be played in 2021 with dates yet to be confirmed.
The 2022 competition will return to its normal format from then onwards.
Haggerty said: "Earlier this year, we took the difficult but necessary decision to postpone the first edition of the new-look Fed Cup in Budapest due to the COVID-19 pandemic.
"While it is regrettable that the Finals will not be able to take place this year, we are confident that we will be able to host a superb event in Budapest in April 2021.
"We would like to thank our partners, the Hungarian Government, for their hard work and continued commitment to the competition."