"I can't say anything and I won't know anything for sure before it becomes official," the Brit said with a broad grin on his face before the start of the Tour de France second stage in the Belgian town of Vise.
The British selection for the road race and individual time trial in London is to be announced on Tuesday. Last month, Millar was included in a shortlist of eight riders for the Olympic road race team.
British Cycling performance director Dave Brailsford, on the Tour as the manager of Team Sky, declined to make any comments on the squad before Tuesday.
Asked about his hopes of being retained, Millar added: "I already made the final cut, so why not?"
The 35-year-old was banned for two years in 2004 after he admitted taking the banned blood-boosting drug EPO and was only cleared to compete in the Games after the British Olympic Association's life-time ban on drugs cheats was declared invalid by the Court of Arbitration for Sport in April.
Millar, who has won three Tour de France stages in his career, was ill before this year's prologue in Liege, but recovered enough to start the race.
"I was worried, but not for the Olympics, I was worried for the Tour," he said.