One Direction's world tour 2014 is about to break records set by U2 and The Rolling Stones: ticket sales are likely to earn One Direction an estimated $1 billion.

One Direction's "Where We Are" stadium tour in 2014 and early ticket sales have put them in line to break records by achieving huge ticket sales in a single year, CTV News reports.

U2 and The Rolling Stones hold the top two spots at the moment, with tour earnings of £467 million (about $764 million) and £341 million (about $558 million) respectively, according to the website.

Currently, One Direction have 88 dates set for their 2014 tour across Europe, the US and South America, with 80,000-seater venues already selling out.

A US rep told The Sun on Sunday newspaper: "Demand was so enormous for 'Where We Are' tickets that 21 American dates had to be added to the original schedule," CV News reports.

"It is absolutely conceivable that still more could be squeezed in before the end of 2014 but that will ultimately be up to the band and its management."

PR Newswire previously reported that that "Where We Are" One Direction tour may be "one of the biggest tours of 2014, having sold out stadiums across the United States and Canada." One Direction has even had to add second shows in select markets that have already sold out. At least 1 million tickets were moved in North America alone for the "Where We Are" tour.

Meanwhile, MTV UK reports that One Direction was spotted shooting the video for "Midnight Memories" in London over the weekend.