Story highlights Sanders forgot where to go Tuesday and headed into the Republican lunch instead

He quickly realized his mistake and turned around

Washington (CNN) It's been a while since Bernie Sanders has attended the weekly Senate Democratic lunch in the Capitol.

So long, in fact, he forgot where to go Tuesday and headed -- with his large Secret Service detail in tow -- into the Republican lunch instead.

He quickly realized his mistake and turned around. When a reporter noted, "wrong room," Sanders replied, "Thank you" as he made his way to the Democratic gathering.

Sanders, the Vermont senator and Democratic presidential candidate, has been largely absent from Capitol Hill while campaigning against Hillary Clinton for the Democratic nomination.