Madonna
Madonna joins Twitter for a day, invites Justin Beiber to join the tour.

After the huge success of her half-time performance at the 2012 Super Bowl and an adoring audience of over 114 million viewers worldwide, pop star Madonna is preparing for her 2012 World Tour.

The tour will be her longest one yet and will cover 90 cities. The 53-year-old entertainer will begin her tour on May 29 in Tel Aviv, Israel. The tour will go through 26 European nations, after which it will shift to North America.

Fans have been angered by the steep ticket prices - in the US they cost between US$80 and US$125 (£50-£80).

Her latest album, MDNA, will be released on March 26. Her last tour, "Sticky and Sweet", ended with 85 dates. The upcoming 2012 tour is expected to be one of the biggest grossers ever; her last concert sold a whopping 75,000 tickets in London... the expectations, needless to say, are higher this time around.

To register for tickets, visit Madonna's official Web site... Check out Madonna's 2012 World Tour dates...

Europe:
May 29, Tel Aviv, Israel Ramat Gam Stadium - On Sale Feb. 10
June 3, Abu Dhabi Yas Arena - On Sale Feb. 27
June 7, Istanbul, Turkey Turk Telecom Arena - On sale soon
June 11, Zagreb, Croatia Maksimir Stadium - On Sale Feb. 17
June 14, Milan, Italy Stadio San Siro - On Sale Feb. 13
June 16, Florence, Italy Stadio Franchi - On Sale Feb. 13
June 20, Barcelona, Spain Palau Sant Jordi - On Sale Feb. 16
June 24, Coimbra, Portugal Estadio Cidade de Coimbra - On Sale Feb. 11
June 28, Berlin, Germany O2 Arena - On Sale Feb. 13
July 2, Copenhagen, Denmark Parken Stadium - On Sale Feb. 13
July, 4 Gothenburg, Sweden Ullevi Stadium - On Sale Feb. 17
July 7, Amsterdam,The Netherlands Ziggo Dome - On Sale Feb. 11
July 12, Brussels, Belgium Stade Roi-Baudouin - On Sale Feb. 17
July 14, Paris, France Stade De France - On Sale Feb. 14
July 17, London, UK Hyde Park - On Sale Feb. 10
July 21, Edinburgh, UK Murrayfield Stadium - On Sale Feb. 10
July 24, Dublin, Ireland Aviva Stadium - On Sale Feb. 17
July 29, Vienna, Austria Ernst-Happel-Stadion - On Sale Feb. 24
Aug. 1, Warsaw, Poland National Stadium - On Sale Feb. 17
Aug.7, Moscow, Russia Olimpiski Arena - On sale soon
Aug.8, St. Petersburg, Russia SKK Arena - On sale soon
Aug. 12, Helsinki, Finland Olympic Stadium - On Sale Feb. 14
Aug. 15, Oslo, Norway Telenor Arena - On Sale Feb. 20
Aug. 18, Zurich, Switzerland Stadion Letzigrund - On Sale Feb. 24
Aug. 21, Nice, France Stade Charles-Erhmann - On Sale Feb. 14

North America:
Aug. 28, Philadelphia, PA Wells Fargo Center - On Sale Feb. 13
Aug. 30, Montreal, QC Bell Centre - On Sale Feb. 18
Sep. 1, Quebec City, QC Plains of Abraham Site - On Sale Feb. 17
Sp. 4, Boston, MA TD Garden - On Sale Feb. 13
Sep. 6, New York, NY Yankee Stadium - On Sale Feb. 13
Sep. 10, Ottawa, ON Scotiabank Place - On Sale Feb. 13
Sep. 12, Toronto, ON Air Canada Centre - On Sale Feb. 13
Sep. 15, Atlantic City, NJ Boardwalk Hall - On Sale Feb. 27
Sep. 19, Chicago, IL United Center - On Sale Feb. 13
Sep. 23, Washington, D.C. Verizon Center - On Sale Feb. 13
Sep. 29, Vancouver, BC Rogers Arena - On Sale Feb. 13
Oct. 2, Seattle, WA Key Arena - On Sale Feb. 13
Oct. 6, San Jose, CA HP Pavilion - On Sale Feb. 13
Oct. 10, Los Angeles, CA Staples Center - On Sale Feb. 13
Oct. 13, Las Vegas, NV MGM Grand - On Sale Feb. 27
Oct. 16, Phoenix, AZ US Airways Center - On Sale Feb. 27
Oct. 20, Dallas, TX American Airlines Center - On Sale Feb. 27
Oct. 24, Houston, TX Toyota Center - On Sale Feb. 27
Oct. 27, New Orleans, LA New Orleans Arena - On Sale Mar. 5
Oct. 30, Kansas City, MO Sprint Center - On Sale Mar. 5
Nov. 1, St. Louis, MO Scottrade Center - On Sale Mar. 5
Nov. 3, St. Paul, MN Xcel Energy Center - On Sale Feb. 27
Nov. 10, Cleveland, OH Quicken Loans Arena - On Sale Mar. 5
Nov. 15, Charlotte, NC Time Warner Cable Arena - On Sale Mar. 5
Nov. 17, Atlanta, GA Philips Arena - On Sale Mar. 5
TBC, Miami, FL, To Be Confirmed, - On Sale Soon

Check Out the Official World Tour Trailer Here...