Clarke, who has been put through his paces at fitness testing following hamstring and back injuries, will make his tournament bow at the Gabba in Brisbane on Saturday.
Clarke has not played an international since December but did run 12th man duties for Australia in their 111-run win over England in their World Cup opener.
Coach Lehmann was brief in his confirmation of Clarke’s return, telling reporters: “He’s playing, mate, he’s defintiely playing”.
Clarke said the decsion had been made – with selectors and medical staff – to miss the opening match against England to give his body more time to recover.
“We had a good conversation last week. We thought it was in my best interst and the team’s best interest to not play against England, give myself another week of preparation and training,” Clarke said.
“And I think at this stage the selectors are really happy.”