London - Boris Becker hailed the ATP Cup team competition as a perfect way for players to launch the new season, saying it gave them a chance to face "the very best".
A Grigor Dimitrov-led Bulgaria was among the final six teams announced on Thursday for the event in Australia in January.
Chile, Poland, Uruguay, Moldova and Norway were the other countries to make the grade, based on the ranking of their number one singles player at the second entry deadline of November 13.
The rest of the 24-nation field was announced in September, although Switzerland later pulled out after Roger Federer opted to skip the tournament.
Speaking at the ATP Finals in London on Thursday, Germany captain Becker said: "I think there is no greater way to get ready for the season but play against the very best."
When asked whether the sport could sustain a new team competition alongside the Davis Cup, he added: "The good news is there are strong interests in tennis.
"A lot of people want to participate. A lot of people want to organise. There is a lot of money at stake, a lot of points. That's the good news."
Austria captain Thomas Muster also said the event was an ideal launching pad for the new season.
"The timing is perfect because the players are coming out of the winter break," he said. "They have actually practised a lot on their game and different things."
The field will be split into six groups across Sydney, Brisbane and Perth.
As the highest-qualifying country at the second deadline, Bulgaria replace the Swiss and join Belgium and the Andy Murray-led Great Britain in Group C in Sydney.
The championship takes place from January 3 to 12 in the lead-up to the year's first Grand Slam, the Australian Open in Melbourne.
Novak Djokovic will begin his 2020 season representing Serbia with Dusan Lajovic in Brisbane, against France, South Africa and Chile.
World number one Rafael Nadal will kick off his campaign in Perth alongside Roberto Bautista Agut facing Japan, Georgia and Uruguay.
Eight teams - with up to five players each - will emerge from the round-robin stage to compete in the knockout phase in Sydney until one is left standing, with ties comprising two singles and one doubles match.
Most of the world's top 30, minus Federer, are taking part.
The new-look start to the year offers Aus$22 million (US$15 million) in prize money and a maximum of 750 singles and 250 doubles ATP rankings points.
It will be held on the back of a revamped Davis Cup, run by the International Tennis Federation this month, bringing together 18 nations in one place for a week at the end of the 2019 season.
ATP Cup draw:
Group A (Brisbane) - Serbia, France, South Africa, Chile
Group B (Perth) - Spain, Japan, Georgia, Uruguay
Group C (Sydney) - Bulgaria, Belgium, Great Britain, Moldova
Group D (Perth) - Russia, Italy, USA, Norway
Group E (Sydney) - Austria, Croatia, Argentina, Poland
Group F (Brisbane) - Germany, Greece, Canada, Australia