But for what, exactly?
"Currently ..." Justin Timberlake said, while posting a photo from the studio with Pharrell, as if to tease new music.
These two have history: As one half of the Neptunes, Pharrell helped produce the majority of Justin's 2002 debut Justified, including lead single "Like I Love You" featuring Clipse. But whether their session was for Justin's follow-up to 2013's The 20/20 Experience is hard to say.
Earlier this year Justin signed on as executive producer for DreamWork Animation's Trolls soundtrack. This studio session could be for a children's song, which isn't necessarily a bad thing. "Happy" was for Despicable Me 2 after all.
See the pic of Justin and Pharrell reunited below.