Lynn joins fellow British racer Sam Bird in testing for the Japanese squad on 22 November, the day after Lynn takes part in the GP2 race that is on the same bill as the FIA WEC finale.

Toyota was initially planning on just testing Bird, but the deal to test Lynn was concluded the week after the Shanghai FIA WEC event earlier this month. Mike Conway will act as a benchmark for Bird and Lynn at the test.

Lynn, who has raced exclusively in single-seaters during his professional career, is well versed in endurance racing as his father Shaun regularly competes in both contemporary and historic sportscar racing.

Toyota has a 2016 place up for grabs in its two car squad following the retirement of Alexander Wurz, but Motorsport.com understands that Kamui Kobayashi is set to be announced as a full time driver in Tokyo next February.

Bird or Lynn could both be considered as official reserve drivers for 2016 when Toyota will race an all-new petrol turbo-powered LMP1 challenger, to be known as the Toyota TS 050 HYBRID.