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Willis won six matches to qualify last year, before beating a top-100 player in the first round and losing to Roger Federer on Centre Court in the second.
He will definitely be at Wimbledon again this year as he has received a wildcard for the doubles.
Seven Britons have been given wildcards for the singles main draws.
They are Naomi Broady, Heather Watson, Laura Robson, Katie Boulter in the women's draw, plus Brydan Klein, Cameron Norrie and James Ward in the men's competition.
All are ranked inside the world's top 250 with the exception of Ward, who has spent much of the last year on the sidelines with a knee injury.
Wimbledon runs from Monday, 3 July to Sunday, 16 July.
German Tommy Haas, a Wimbledon semi-finalist in 2009, has also been given a wildcard, along with Canadian Denis Shapovalov in the men's draw.
Shapovalov, 18, was defaulted in a Davis Cup match against Kyle Edmund in February after hitting a ball in frustration that fractured umpire Arnaud Gabas's eye socket.
He beat Edmund at the Aegon Championships in London on Monday at Queen's Club.
BBC tennis correspondent Russell Fuller
"Willbomb's on fire .. Federer is terrified" was one of the more unusual chants that could be heard on Centre Court last year as Willis played the seven-time champion in the second round.
Willis had been playing mostly in the French and German leagues and was ranked 772 in the world prior to the Championships. He has played sparingly in the past 12 months, and, now ranked 387, has won just under £3,000 on the Futures circuit so far this year.
Many other British players will have a chance to compete in qualifying - including the 18-year-olds Jay Clarke and Katie Swan and 19-year-old Gabriella Taylor.
Taylor spent four days in intensive care after losing her girls' quarter-final match last year, and Scotland Yard later investigated claims that she had been poisoned.
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Britain's Marcus Willis has been awarded a wildcard into qualifying for Wimbledon after his fairytale run at last year's tournament.