The comedian first made the surprise announcement alongside co-star Sian Gibson live during BBC Children in Need last year.
Now the BBC has confirmed the shows will air in May this year. The first will air at 10PM on Monday, May 7 while the second will air on Monday, May 28.
Car Share viewers were left in dismay at the end of the second series when Kayleigh stepped out of John’s car and his life forever. Fans even set up online petition demanding a conclusion to the series which gathered over 100,000 signatures.
Peter Kay said in 2017: “We were completely overwhelmed by the response and even though we've no plans to write a third series we knew we couldn't end the story there.”
A special finale episode to be broadcast this year (May 28) will reveal just what happens next to John and Kayleigh.
Before then, on May 7, BBC One will broadcast a special episode called Car Share: Unscripted which will follow John and Kayleigh home on their daily commute only the entire episode will be completely improvised.
Peter said last year: "We were always very fond of ad libbing around the script when we were filming the series so we decided to see what would happen if we took the script away and just relied on just our chemistry alone, reacting to whatever came on the radio."
Charlotte Moore, Director of BBC Content commented: "I know it will be music to the ears of millions of fans of Peter Kay's joyous award winning comedy to hear that Kayleigh and John will be coming back for one last time with a very special finale episode in 2018."
Shane Allen, Controller Comedy Commissioning added: "Car Share has been the hit comedy of 2017 with audiences of over 11 million. This new finale is going to be the TV comedy equivalent of The Space Landing, ‘Who Shot J.R.?’ or The Olympics Opening Ceremony depending on how old you are”