A companion show is a non-fiction show intended as a complement to another show, usually fiction. You usually get one episode of the companion show for each episode of the main show. There are two main types of companion show, although there is some overlap between the two. The first is a documentary-style show, offering a look behind-the-scenes of the main show, showing how special effects are done, and with the cast and crew discussing the characters, plotlines, sets and costumes, and anything else the producers of the show want to highlight. The style is similar to the sort of featurette you might get on the DVD of the series. The second type is a more fan-based show. The presenters will almost always be telegenic fans or popular former actors or runners-up of the main show who transitioned to hosting, and discuss the latest episode, highlighting their favourite and least favorite moments and characters, as well as commenting on the unfolding storylines and possible theories of how the plot will develop. Expect some audience involvement, by e-mail, text message or telephone. Some shows have a studio audience to lend their comments. Reality TV shows sometimes have companion shows as well, although usually some of the elements of companion shows are included in the main show.
- In the United Kingdom, Heroes has both types of show. Heroes Unmasked is a documentary (with voice-over by Anthony Head), focusing on different elements (usually different characters) of the show each week, and broadcast after each episode on BBC2. Heroes: The Official Radio Show is a fan-based radio show (with podcast), with fan e-mails read out (and some fans phoning in).
- For season two, G4 aired an American companion show that, over its run, managed to get most of the cast on. It was called The Post Show.
- Doctor Who has two companion shows. Doctor Who Confidential is a behind-the-scenes show, and Totally Doctor Who is a children's show, with a mixture of things including games, behind-the-scenes segments and reviews of the episode; perhaps most notably it was through Totally that the series three animated serial The Infinite Quest was shown (with voice acting from Anthony Head). As on October 2011, both shows have been cancelled. In 2014, a much shorter version of Confidential was introduced on the red button channel, called Doctor Who Extra.
- Torchwood has its own version of Doctor Who Confidential with much shorter episodes, known as Torchwood Declassified.
- Hustle has the companion The Real Hustle, intended to help the audience avoid being conned. However it is so distinct from Hustle it is fairly easy to watch in its own right.
- Strictly Come Dancing has a weekday BBC2 show called Strictly Come Dancing: It Takes Two, with interviews and behind the scenes footage, among other things. It also features some truly awful puns in its captions. Such as (brace yourself): "The Penny's Dropped" for Penny Lancaster-Stewart after she recently went out of the competition.
- The second season of 24 in the UK had Pure 24.
- LOST in the UK had UK Lost (a podcast) while Season 2 was being shown on Channel 4. Presented by Ian Lee and others, it was the fan-based variety of show, including, among other things a discussion of fan theories e-mailed in, including more than a few Epileptic Trees. It also provide updates on The Lost Experience the Alternate Reality Game. When the show moved to Sky, the name changed to The Lost Initiative.
- Big Brother had Big Brother's Little Brother which features, you guessed it, interviews and behind-the-scenes footage. On top of that there was Big Brother's Big Mouth which was basically an internet forum on TV. When the show moved from Channel Four to Channel Five, the spin-offs were replaced with a new show, Big Brother's Bit On The Side.
- The Canadian version of the show started the Big Brother Side Show in season 2, where previous houseguests Peter and Gary talked about the events in the the house and interview the most recent evictee.
- Trope-within-a-trope: companion shows typically have punning titles: Strictly Come Dancing: It Takes Two, Dancing on Ice: Defrosted, Space Cadets: The Satellite Show, Hell's Kitchen: Extra Portions and so forth. Naturally there are exceptions: Dancing on Ice Exclusive was particularly uninspired example.
- The Xtra Factor for The X Factor
- Britain's Got More Talent for Britain's Got Talent
- The Apprentice - You're Fired for the UK's The Apprentice
- I'm a Celebrity Get Me Out Of Here Now for I'm A Celebrity, Get Me Out Of Here!
- After AMC's attempts to lead-out of The Walking Dead with reality shows failed, The Talking Dead with Chris Hardwick discussing the episode afterwards was created. After it did unexpectedly well, AMC decided to have the last episodes of Breaking Bad have another Hardwick-hosted show called Talking Bad lead out of that.