How do you know, do you have a source?

Yeah I saw those clips, they must have been from previous seasons because Real Time is a live program.

In the absence of any other verifiable clues that video may be your best bet at clues as to who is an upcoming guest. I agree that this show seems to be saying that it is all live in promotional material, but it has had pre-recorded segments in the past."during the (writer's) strike, Maher aired pre-recorded interviews by himself with everyday people about the election and other issues after the opening monologue." http://en.wikipedia.org/wiki/Real_Time_with_Bill_Maher I don't watch this show to be able to say for sure that I recognize all the segments in this ad as past episodes. The topics sound quite new. If the show has been off the air for a while with his movie then these could be new promo film clips. It sounds a bit strange to me to advertise a "new" show and show "old" clips. If you watch the Craig Ferguson comedy show, they have announced quite a few times that some segments of the show have been pre-recorded, but they never admit to which segments. The policy of this show might be to not announce anything like this in order to preserve the live feel of it but it is still possible that some snippets are prerecorded. When you read press about certain stars they will often fly into a city for a day or two and do segments of shows one after the other. Due to their scheduling, certain famous people who have their own scheduling responsibilities elsewhere may need to pre-record a segment in order for them to be on the show at all. Even if these are only promo new clips, and the Bill Maher show will all be shown live, if you scan the other talk shows and comedy shows you will see some of the same guest names reappear on various shows. So, it is still likely that these people will be upcoming guests for the season. It is probably easier to pay them for an interview plus three seconds worth of dialog. I can't see them making a promo video of a new season, and everyone then may expect these people to reappear in the season later, and none of these guests ever appear on the show again - do you get what I am saying? That would be misleading - so do you think these are all red herrings and none will be guests? The three I mentioned by name are popular celebrities that have appeared on many talk shows so it would be reasonable to expect that they could very well appear on this show also. That may be the best answer you can get in advance like that because it is put out on the official show site. Even if you asked Bill Maher, there probably is a policy in place preventing him from releasing all the secrets of the upcoming show. Guests probably know way in advance who will be on the show because they have to schedule and plan them, but since no one seems to be finding proof of upcoming guests there must also be a secrecy clause in their contract if they wish to be paid for their work. That probably just adds to the anticipation and excitement that waiting for the show generates until the official schedule comes out on the 24th of each month. Very clever. It will be interesting to see whether any or all of these guests do appear on the show this upcoming season.