Evans confirmed the news as he tweeted a picture of himself LeBlanc and The Stig.
The revamped version of the BBC show is due to air in May
"As a car nut and a massive fan of Top Gear, I'm honoured and excited to be a part of this iconic show's new chapter. What a thrill!" LeBlanc said.
Evans said LeBlanc, who is best known for his role as goofy lothario Joey in Friends, is a "lifelong petrolhead".
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"Acting out our craziest car notions on screen is a dream job and I know we'll both be debating some epic road trip ideas," Evans said.
LeBlanc appeared on the original show in 2012 and set the fastest-ever time for their Star in a Reasonably Priced Car segment.
According to the official Top Gear website, he set an unbeaten lap time of 1m 42.1s in a Kia cee'd.
The choice has been popular on social media.
