According to http://www.dailymail.co.uk/:
This huge hound officially entered the record books today as the world's tallest dog - standing more than seven foot on its hind legs.
'Giant' George claimed the prestigious title after Guinness Records officials measured him up at 43 inches from paw to shoulder, or 7ft 3in when 'standing' on his back legs.
The four-year-old great dane weighs a staggering 17.5 stone and consumes 110lb of food each week.
http://www.dailymail.co.uk/news/worldnews/article-1252928/Measuring-7ft-Giant-George-enters-record-books-worlds-tallest-dog.html
