Chris Evans has announced that he's stepping down from his role on BBC's Top Gear after just five episodes with the show. "Gave it my best shot but sometimes that's not enough," he tweeted. "I feel like my standing aside is the single best thing I can now do to help the cause." The widely-watched show had suffered a drop in ratings and hit a low for the series on Sunday night, with an average of only 1.9 million viewers. Evans was co-hosting the show with former Friends star Matt LeBlanc. Evans released a statement through the BBC, saying, "I have never worked with a more committed and driven team than the team I have worked with over the last 12 months." He added, "I remain a huge fan of the show, always have been, always will be."