Clarkson's appearance on the anniversary special of TFI Friday will be the first time fans have seen him on TV since he was dropped from the hit motoring show for assaulting a colleague.
Evans sparked an online frenzy at the weekend when he revealed he was making a "secret Top Gear film", but sources close to the show said the pair were in fact filming for the one-off episode of Evans' programme which was a staple of Channel 4's schedule in the 1990s.
The live special will feature guests including Evans' old sidekicks Danny Baker and Will Macdonald. The original show was a huge hit but regularly courted controversy, notably when guest Shaun Ryder swore and was subsequently banned from appearing on the channel again, though the Happy Mondays frontman is due to appear this Friday.
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Top Gear's future was thrown into the air earlier this year when Clarkson was suspended after assaulting producer Oisin Tymon. It is still unclear what will happen to the show after it was reported co-presenters Richard Hammond and James May have been offered deals in the region of £1 million a year to stay with the BBC.
That deal, which would make the pair among the corporation's highest earners, is said to be part of a plan to include a different guest host on each show rather than directly replacing Clarkson.
All three men's contracts ran out earlier this year and the BBC refused to renew Clarkson's after his much-publicised attack.
Andy Wilman, Top Gear's former executive producer - and an old school friend of Clarkson - has left the show, which sparked rumours he was joining up with all three men to make an alternative programme, with Netflix and ITV among the broadcasters rumoured to be in the running to screen it.
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