Pharrell Williams happily clawed back his singles chart throne back from party pair Pitbull and Ke$ha - after just one week in their shade.
The 40-year-old was knocked off the top by the Miami rapper's track Timber last week, but made it back to the top with Happy for a second non-consecutive week.
Pharrell hit the big time in 2013 after he was involved in two of the biggest-selling singles of the year - Get Lucky by French electro duo Daft Punk and Blurred Lines with Robin Thicke and TI - before ending at the top with his new solo track.
Meanwhile, Swedish DJ Avicii spent another week at number three with Hey Brother, his sixth top 10 hit, while Jason Derulo hung on to number four with Trumpets.
Rapper Fuse ODG scaled nine places to number five with Million Pound Girl (Badder Than Bad) scoring his highest UK chart position to date, after debut single Antenna peaked at number seven last year.
In the albums chart, Ellie Goulding fended off stiff competition from Beyonce to retain her crown.
Goulding's second album Halcyon finally reached the summit last week after 65 weeks in the top 75, but came under threat this week from Queen Bey's self-titled full-length effort.
The 27-year-old singer from Lyonshall in Herefordshire boosted her reputation for beating back American superstars after already keeping Lady Gaga off number one in the singles list with her hugely popular track Burn.
Beyonce's sales saw Gary Barlow slip one place to number three with fourth studio album Since I Saw You Last.
Completing the top five were John Newman's Tribute, which climbed one place to number four, while Bastille's Bad Blood also advanced one spot, rising to number five.