UPDATE: 

Letterman tickets are sold out as of 12:30, said Christy Chambers, assistant director of marketing and communications at John R. Emens Auditorium. 

EARLIER:

If you want to get a ticket to see David Letterman, you'd better hustle over to the box office. 

Today at noon, there were less than 50 tickets left to see Letterman speak.

Letterman will be speaking on Nov. 30 at John R. Emens Auditorium with filmmakers Spike Jonze and Bennett Miller.

Tickets, which went on sale on Nov. 13, are free for everyone. Tickets opened up to the general public today. 

For those who already have tickets, make sure you are in your seat by 6:40 p.m. on Nov. 30 or your seat will be given to someone else.