Bryan Bedder/Getty Images for Nickelodeon
Even at the age of 41, Pharrell still has a thing for SpongeBob SquarePants.
After rocking SpongeBob SquarePants onesie at the Nickelodeon Kids' Choice Awards last week, the "Happy" crooner took his love for the animated character up a notch with a SpongeBob SquarePants themed birthday bash at Bikini Bottom at Cipriani Wall Street in New York City.
His wife Helen Lasichanh was by his side as he rang in his big 4-1, along with Alicia Keys, Swizz Beatz, Russell Simmons, Angela Simmons, Chanel Iman, Nicky Hilton Rothschild, Josh Lucas and Soledad O' Brien, among others. Q-Tip was also there, serving as the DJ for the evening.
And, yes, Pharrell was wearing The Hat (the green version).
NEWS: Pharrell Williams Joins The Voice as Season 7's New Coach!
Dimitrios Kambouris/Getty Images for Nickelodeon
As the party rolled on, the birthday boy and his guests munched on a cake shaped like the Nickelodeon show's character Krabby Patty, and he also posed for pictures with some of his favorite characters, including SpongeBob, Patrick and Squidward, according to the Daily Mail.
Several of Pharrell's friends also sent birthday wishes via Instagram and Twitter, with One Direction's Liam Payne tweeting, "Happy birthday @Pharrell hope you have a great day look forward to getting back in the studio with you next time I'm in Cali."
"Wishing @Pharrella very #Happy birthday," Robin Thicke also tweeted.
"Happy Bday to my brother, @Pharrell!!! Been killing the game forever! And, you still look younger than the rest of us...," Justin Timberlake chimed in.
"Happy birthday pharrell! Love, love your spirit !," Jennifer Hudson wrote on Instagram, sharing a collage of them hanging out.
In addition to his birthday, Pharrell has quite a bit to celebrate this month, including the announcement of his new Voice coach season 7 gig, his performance on Saturday Night Live tonight and a sit down with Oprah Winfrey on OWN'S "Oprah Prime" April 13.