Through the Keyhole is a British comedy panel game show created by the TV producer Kevin Sim and originally presented by Sir David Frost in the studio and Loyd Grossman on location. The location presenter goes around celebrities' houses and a panel of other celebrities in the studio try to guess who the famous homeowner is.

The show was originally produced by Yorkshire Television and was broadcast on ITV from 3 April 1987 to 1 May 1995, then on Sky One from 22 February to 23 December 1996 before moving to BBC One from 5 May 1998 to 2004 and its sister channel BBC Two from 26 February 2006 to 4 June 2008.

In 2013, the show was revived for ITV with Leigh Francis as the host.^[2] In February 2020, it was reported that the programme had been cancelled after six series.^[3]

At the start of each episode, Frost introduces a panel of three celebrities with the catchphrase "And what a panel they are ..." and some gently humorous or mocking descriptions. He then hands over to the location presenter who gives the panellists a guided tour of a property, noting particular items, though there is typically a large amount of misdirection involved as the items pointed out by the presenter are not necessarily the most pertinent clues to the person's identity. Items not specifically mentioned may provide much more useful clues. Once completed, Frost reveals the identity of the guest to the audience and the panel are given turns at guessing their identity. The audience participate with varying degrees of applause according to the accuracy of the panellists' guesswork.

The panellists are either successful at identifying the guest or Frost reveals their identity, after which they are interviewed and given a key-shaped trophy as a memento. Starting during Loyd Grossman's reign as location presenter, the geographic spread was extended with one of the properties on each episode being located in the US and one in Europe. When Stefanie Powers joined in 2007, she was based in the US and conducted the US property tours, whilst in the UK Lisa Snowdon conducted the European part.

In 2015, the Dutch SBS6 channel broadcast the Dutch version, called Met de deur in huis, hosted by Kees Tol. In this show, comedian Tineke Schouten visits the houses of Dutch celebrities. The panel (Maik de Boer, Patty Brard and Ruben van der Meer) have to guess whose house she is in. In 2016, a second series aired on SBS6.