Brown's follow-up to 2011's F.A.M.E. replaced Linkin Park's Living Things at the summit and outsold the number two album, Overexposed by Maroon 5, by 11,000 copies.
Linkin Park slipped to third, as Ed Sheeran's + dropped one place to number four. Emeli Sandé's Our Version of Events - which is the second biggest-selling album of 2012 so far, behind Adele's 21 - held on to the number five spot.
Adele's record-breaking sophomore album rose from number 15 to number nine, after slipping out of the top ten last month for the first time since its January 2011 release.
Aside from Brown's Fortune, the Top 40 only saw one new entry from Mary Chapin Carpenter, whose album Ashes and Roses went to number 26.
Katy Perry's Teenage Dream, David Guetta's Nothing But The Beat and Train's California 37 all rose seven places, to 27, 32 and 18 respectively.
Meanwhile, Paul Simon's Graceland was the highest climber, up 39 places to six ahead of his appearance at Hard Rock Calling, while Jack White's Blunderbuss also re-entered the chart at 40.
Watch the video for Chris Brown's 'Don't Wake Me Up' below:
Source: Official Charts Company
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