Conan O'Brien, one of our favorite Irish Americans, is back at work after banging his head hard during a sketch for the Tonight Show.

O’Brien returned to The Tonight Show last night in good shape after a nasty accident last week when he slammed down on to the stage after running into the live taping with "Desperate Houseswives" star Teri Hatcher.

O'Brien had just run a triathlon with Hatcher and the plan was for the pair of them to run straight on the set for the chat show.

O'Brien said he planned to slide across to the desk but he slipped on the stage and slammed back on to his head.

He says he doesn't remember anything after that and TV bosses took the show off the air while he recovered.

Happily, he looked fine last night and we hope he stays fine.

No more running onto slippery surfaces Conan!