Korean superstar Psy has taken Justin Bieber down.

On Saturday, his "Gangnam Style" video surpassed Justin's "Baby" video to become the most-watched YouTube video of ALL TIME.

As of late last night, "Gangnam Style" had over 823 MILLION views, while "Baby" followed with around 805 million.  Justin's "Baby" video was posted in February of 2010.  "Gangnam Style" hit the Internet in July.

"Baby" enjoyed a TWO-YEAR REIGN as the most-watched video.  It had been YouTube's most popular video since July of 2010, when it took the crown from Lady Gaga's video for "Bad Romance".

According to YouTube, "Baby" is still getting between 350,000 and 500,000 views a day, but "Gangnam Style" is crushing that with 7 to 10 MILLION views a day.