Eight-time champion Roger Federer was confirmed as the second seed for Wimbledon on Wednesday, bumping Rafael Nadal down to third despite being ranked below the Spaniard.
Defending champion Novak Djokovic tops the draw while new world No 1 Ash Barty is top seed in the women's singles.
South African Kevin Anderson, runner-up to Djokovic last season, is fourth seed despite falling to eighth in the ATP rankings as Wimbledon used its special formula once again.
Twice Wimbledon champion Nadal will be seeded three, meaning he is likely to have to beat both Federer and Djokovic to claim his first title at the All England Club since 2010.
The Spaniard was critical of the Wimbledon's seedings formula this week, saying "it's not a good thing" that the grass-court event is the only one of the four grand slam tournaments that does not stick rigidly to ATP rankings for seedings.
Wimbledon uses form over the past 24 months on grass to tweak the positions of the top 32 players in the men's draw.
While the women's seedings are in line with the WTA rankings, Wimbledon reserves the right to change the order to create "a balanced draw".
Anderson's promotion is bad news for French Open runner-up and world No 4 Dominic Thiem who drops to fifth seed and could play Djokovic, Federer or Nadal in the last eight.
Former runner-up Marin Cilic moved up from a world ranking of 18 to the 13th seeded spot.
Seven-time champion Serena Williams is seeded 11th as per her WTA ranking. Last year the American was bumped up to 25th seed despite being ranked 183rd after returning to the tour following the birth of her daughter.
McEnroe cool on Murray hopes
Meanwhile, John McEnroe remains cautious about Andy Murray's hopes of a successful singles comeback.
The former world No 1 made a brilliant return to the match court at Queen's Club last week following a second hip operation in January, winning the doubles title with Feliciano Lopez.
Murray has also restricted himself to doubles at Wimbledon but spoke about the possibility of a singles return as early as the US Open at the end of August.
McEnroe is thrilled to see Murray back but is not reading too much into his doubles achievements.
"I never got to win the Heavyweight Championship” 😆
— Amazon Prime Video Sport (@primevideosport) June 19, 2019
Flying elbows, leg drops & tap outs 🤕 @andy_murray on his childhood wrestling antics with brother Jamie… pic.twitter.com/HNdSNnhV2o
Speaking on behalf of ESPN.co.uk, the American said: "Doubles is obviously a completely different animal than singles. Best of five [sets] is totally different than best of three.
"But it was nice to see him eager and into it and looking like he was relatively healthy. You can't really determine it until he starts playing singles matches and how the body reacts if you're on a hard court, for example, as opposed to grass.
"It looked very promising, which is great, and I think everyone wants him to be able to come back and then be able to retire on his own terms."
In Murray's absence from singles, British hopes of a title challenger rest with Johanna Konta following her surprise run to the French Open semi-finals.
