The former Test opener is filling in for his ex-team-mate, who developed deep vein thrombosis earlier this year, during next month's one-day tri-series in the Caribbean which also features South Africa.
While Lehmann has no plans to step away from the job in the foreseeable future, he has already anointed Langer as his potential replacement.
"I think the natural progression would be to one day coach the Australian cricket team, or certainly that would be an aspiration," Langer told the Cricket Australia website ahead of the team's departure.
"So who knows what will happen in the future."
Also Read
Langer is currently coaching Western Australia in the Sheffield Shield and the Perth Scorchers in the Twenty20 Big Bash League, and will fill the national job for the first time.
Prior to his Western Australia appointment, Langer, who played 105 Tests and scored more than 7,500 runs, worked as a specialist batting coach with the Australian team.
Australia begin the tri-series in Guyana on June 6
against South Africa before facing the hosts four days later at the same venue.
The round-robin tournament sees teams play three matches against each opponent, with the top two advancing to the final on June 26 in Barbados.
"Certainly this West Indies tour I'm looking forward to it, but I'm doing it with the respect it deserves," said Langer.
"I'm helping Darren out, I'm going to make sure the ship keeps running nice and smoothly in his absence and I think that's the respect I can give him, it's the respect I would expect if someone else was doing (for me) what I'm doing for him.
Lehmann will enjoy his first extended break since taking on the role of national coach in 2013.