Millar last wore the coveted tunic in 2000 when he won the prologue at Futuroscope, and on Tuesday's 29.5km race against the clock the big Scot will see whether recent efforts to train specifically for the Tour have paid off.
Giving his American team Garmin their first stage win on their race debut would be a huge boost to both, although with world time trial champion Fabian Cancellara of CSC starting as the big favourite, Millar knows it won't be easy.
"For me, the big favourite is Cancellara," said Millar. "He's beatable, but I'm going to have to have the performance of my life to beat him."
Millar's team would cherish a stage win on their debut, but with the big Scot among the many riders who are only seconds adrift of race leader Alejandro Valverde of
One of the Scot's team managers, former Australian pro Matthew White, feels a top five place on the 29.5km course is well within reach.
"The course isn't so technical, but it's going to be really fast," said White. "David is well capable of a top five place. Cancellara will be the man to beat, but he's beatable and David has shown he's on great form."
But for Garmin team manager Jonathan Vaughters, the man who effectively won the team - formerly known as Slipstream - a place at the Tour on a strict anti-doping pledge, a stage win comes second to the bigger prize on offer.
Before the end of Monday's third stage, Millar was only 01sec behind Valverde, and with a six-second advantage on Cancellara. A top five place for Millar would be welcome for Vaughters, especially if Cancellara finishes behind him.
"I believe David can easily finish in the top five," he told AFP. "The question really is whether he can beat Cancellara by six seconds, and hold off Valverde. But the real question is whether David can take the yellow jersey tomorrow or not."
The time trial is the first real test for the yellow jersey contenders. And while not a specialist, Valverde will be hoping to limit his losses in the race against the clock to his main yellow jersey rival Evans, whom he beat in the third stage time trial, over an undulating 31km, of the Dauphine Libere in June.
Tuesday's flatter course around Cholet is likely to be perfect for riders like Millar and Cancellara.
CSC team manager Bjarne Riis has similar hopes for Cancellara: "I hope (Cancellara) will go fast. If he wants to win and get the yellow jersey he needs to go fast."
Whatever the result, Vaughters is already happy with the positive changes, albeit late, that Millar has made to his approach to the world's biggest race.
"I've known David since 1997 and I haven't seen him as motivated as this for the Tour," he added. "It's the first time he's trained very methodically. In the past he's relied mostly on pure talent alone.
"But now he's older, more mature and more focussed and he's trying to make the most of the talent that he has."