WATCH: Fallon sings Neil young classic 'Old Man' alongside Neil Young

Jimmy Fallon sang the Neil Young classic song "Old Man" on The Tonight Show Tuesday.

He was clad in the entire get up — hair and all.

The kicker?

The real Neil Young sang alongside Fallon.

It was Neil Young singing alongside "Neil Young."

WATCH THE VIDEO HERE IF IT DOESN'T DISPLAY ABOVE.