We all knew that Infinity Ward's Call of Duty: Modern Warfare 2 was going to be big, but just how big? Well, according to publisher Activision, the game has sold approximately 4.7 million units across North America and the United Kingdom in its first 24 hours.

These numbers are based on "internal Activision estimates," which also claim the game had the largest opening day sales numbers across all forms of entertainment, raking in an estimated $310 million.

"The Call of Duty franchise has become a cultural phenomenon showing the power of video games as an entertainment medium," Activision CEO Mike Griffith said in a statement. "The shattering of these entertainment records is a testament to the compelling, cinematic and uniquely engaging experience that the Call of Duty brand delivers. Modern Warfare 2 has taken interactive experience to unprecedented heights setting a new standard for entertainment."

For the sake of comparison, Halo 3, which was also deemed to have the biggest launch in entertainment history when it was released in 2007, made $170 million in the US in its first day, and "more than" $300 million worldwide in its first week. Grand Theft Auto IV, meanwhile, released the following year, sold approximately 3.6 million units in its first day, earning $310 million worldwide, and six million in its first week, bringing in an estimated $500 million. It's also important to note that both GTAIV and MW2 are multi-platform games, whereas Halo 3 is an Xbox 360 exclusive.

Whether or not it actually is the biggest launch in history, moving nearly five million units in a day is certainly impressive.