VIDEO : Kendrick Lamar's Surprise 'Untitled Unmastered' Album Tops the Weekly U.S. Billboard 200

LOS ANGELES Rapper Kendrick Lamar dropped a surprise album that went straight to the top of the weekly U.S. Billboard 200 album chart on Monday, following in the steps of Beyonce, Drake and Future. Lamar's "untitled unmastered" album, released March 4 with no prior announcement, sold 178,000 units across album and song sales and streaming activity, according to figures from Nielsen SoundScan. It follows a breakout year in 2015 for Lamar, whose album "To Pimp a Butterfly" won five Grammy awards in February.