Mayor Michael Bloomberg welcomed "Late Show" host David Letterman back to the air after a two-month hiatus by presenting a key to the city Thursday to the show's latest character — Letterman's beard.

Letterman, like NBC's Conan O'Brien, brought his show back Wednesday sporting a beard that was cultivated while the "Late Show" and many other TV shows were dark, deprived of their writers during a strike.

The strike continues, but Letterman is back — with his writers — after reaching a deal with the Writers Guild of America to let them work.

Bloomberg stopped by at the start of Thursday's show.

"I wanted to present a key to the city," he said, holding a case with the symbolic honor.

Letterman thanked him, but Bloomberg said it wasn't for him.

"This is for your beard," the mayor said.