"It's not a decision we made lightly" said Tuke. "Representing your country at Olympic level is the highest honour and we are both incredibly focused on defending the Cup for New Zealand as part of Emirates Team New Zealand. We wanted to ensure we could give both campaigns everything we've got."
Burling added: "We know the combination of Olympic and America's Cup sailing complement each other. It creates a really high-performance environment across all areas of sailing for us to push ourselves and be at the top of our game."
"The main thing we wanted was to be able to give ourselves a fair shot," said Burling told Radio Sport's Jason Pine.
"We've obviously got incredibly high expectations for ourselves and if we wanted to do it, we wanted to do it our way and do it properly. We wanted to have a little bit of time off after the Volvo, which is obviously an incredibly gruelling race, before we made our final decision.
"Now we're both really excited about the challenge. Both of us have always had a pretty special spot for the Olympics, it's what you grow up sailing for as a kid. We both really wanted to take it on again and we're both really excited we've got a pretty good plan in place to be able to execute it as well as we think we can."
The duo has the support of Team NZ and Yachting New Zealand.
"It's great to have them back in the 49er," Yachting New Zealand high performance director Ian Stewart said. "They are special sailors and will strengthen our goal of winning at least three medals in Tokyo but, more than that, their experience and leadership will have a massive impact on the ongoing development of the NZL Sailing Team."
Team NZ COO Kevin Shoebridge continued: "We are happy to have Peter and Blair back as part of the team dedicated to the defence of the America's Cup. Once again, we're fully supportive of them integrating the Olympic 49er campaign with America's Cup commitments.
"Collectively we are an incredibly strong and talented team that is focused on defending the America's Cup and that allows our core sailing team including Peter, Blair as well as Andy Maloney and Josh Junior to remain in peak sailing condition running parallel Olympic campaigns."