Delicore: The line to see Diplo at Katz's After Dark Sunday night

We received some curious queries about the long lines outside the venerable Katz's Delicatessen on Sunday night... as lines of partygoers stretched in both directions here on Houston and Ludlow. (Thank you to Lisa Holiday for the top pic!)

This was billed as "Katz's After Dark" — "Invite only, for the industry by the industry" — and presented by Red Bull, as part of their Summer Sessions series, and the clothing brand Mr. Saturday. 

Attendees received complimentary Red Bull cocktails from 11 p.m. to 4 a.m. ... and the usual Katz's fare.

There were four DJs on the bill, Joey Saturday, Mona Matsuoka, Gonnie Garko and headliner Diplo ...

This appears to be a one-time event, though there is a Katz's After Dark Instagram account in case there's ever a next time.

Katz's previously hosted Vogue's Pre Met Party this past spring.