Lil Jon -- Michelle Obama Can Make Me Do New Things

Lil Jon will do something he's never done before ... but only if Michelle Obama tells him to.

The rapper blew into LAX Wednesday and made it clear ... it was the highest honor that the First Lady parodied his song "Turn Down for What" into "Turnip for What?"

Turns out The White House gave him a heads up.

But what's real ... he'll venture into new territory ... but only IF Michelle gives the order.