Safin, who upset Pete Sampras in straight sets in New York in September to win his first grand slam title, was confirmed on Thursday in the annual mixed team's event in Western Australia.
He will team up with Elena Likhovsteva in a strong Russian team seeded second for the US$1 million eight-nation event from December 30 to January 6.
Switzerland, led by women's world number one Martina Hingis, have been seeded first. She will be partnered by Roger Federer.
The United States were seeded third ahead of defending champions South Africa. Australia, the Slovak Republic and Thailand were also offered places while Belgium and Japan will play off for the final berth.
Teams (prefix number denotes seeding):
Group A
1-Switzerland (Roger Federer/Martina Hingis)
4-South Africa (Wayne Ferreira/Amanda Coetzer)
Australia (Mark Philippoussis/Nicole Pratt)
Thailand (Paradom Srichaphan/Tamarine Tanasurgan)
Group B
2-Russia (Marat Safin/Elena Likhovsteva)
3-United States (Jan-Michael Gambill/Monica Seles)
Slovak Republic (Dominic Hrbaty/Karina Habsudova)
Belgium (Olivier Rochus/Kim Clijsters) or Japan (Takao Suzuki/Ai Sugiyama).