Chris Evans resigns from BBC's 'Top Gear'

Chris Evans has resigned as co-host of the BBC's "Top Gear."

"Gave it my best shot but sometimes that's not enough," he tweeted.

His decision - which he said was made to focus on his radio show - comes after media reports of tension with co-host and former "Friends" star Matt LeBlanc, as well as poor ratings.

LeBlanc reportedly threatened to quit if Evans was not removed first.

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