Rusty met Florida-based Tarver, the star of the Rocky Balboa movie, at a café at Sydney's exclusive Woolloomooloo Wharf, close to where Russ has a home.
Antonio, 42, is Down Under to fight Aussie IBO cruiserweight champ Danny Green, 38, at the Sydney Entertainment Centre on July 20.
Antonio appeared in 2006's Rocky Balboa, when he played Mason The Line Dixon, who fights Rocky when Sylvester Stallone's character comes out of retirement.
Russ played heavyweight boxer Jim Braddock in the 2005 movie, Cinderella Man.