The singer's collaboration with Pharrell Williams and TI is the fastest-selling single of 2013 so far, shifting over 190,000 copies in its first week on sale.
"It is an honour and a pleasure to be number one in the UK," Thicke told The Official Charts Company. "It's something I've always dreamed of, and I am so grateful to all the people who made this dream come true. Thank you!"
Thicke's previous peak in the UK singles chart - and only Top 40 hit - was 2007's 'Lost Without U' at 11.
Naughty Boy and Sam Smith drop a place to two with 'La La La', while Daft Punk slip a place to three with 'Get Lucky'. Passenger also falls just one to four with 'Let Her Go'.
Jessie J enters at five with 'Wild', featuring Dizzee Rascal and Big Sean. It is her seventh UK Top 10 hit, and the first to be lifted from her upcoming second studio album.
Olly Murs rises three spots to six with 'Dear Darlin'. Macklemore and Ryan Lewis slip three to seven with 'Can't Hold Us', as do Rudimental to eight with 'Waiting All Night'.
2 Chainz and Wiz Khalifa drop three to nine with 'We Own It (Fast and Furious)'. Demi Lovato climbs a spot to ten with 'Heart Attack'.
Jennifer Lopez scores her 20th UK Top 40 hit at 17 with 'Live It Up' featuring Pitbull, her third single in three years to feature the rapper.
London MC Stylo G earns his first top 20 hit at 18 with 'Soundbwoy'.
Of Monsters and Men re-enter at 13 with 2012 hit 'Little Talks', after it was performed on The Voice UK last weekend. Daniel Merriweather's 2009 hit 'Red' also climbs back up to 29.
Paramore continue climbing with 'Still Into You', which is now up to a new peak of 15.
Bruno Mars achieves his third Top 40-charting single from his latest album, with 'Treasure' entering at 35. The Script climb back to 37 with their second hit 'The Man Who Can't Be Moved'.
Ellie Goulding climbs back to 39 with 'Anything Could Happen' after she performed on the first Britain's Got Talent semi-final.
Watch the video for Robin Thicke's 'Blurred Lines' below:
Source: Official Charts Company
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