Update: Willow has cleared up the song's genesis:
Original story: By the grace and power of the internet, Michael Cera and Willow Smith have paired up and released the song "twentyfortyeight 2.0." Earlier this month, Smith called Cera "extremely beautiful" in a tweet, and the remark seems to have garnered something of a relationship between the actor and multi-hyphenate teen star. Listen to the lucid track above, which features Smith waxing lyrical about the ways of the world.
Earlier this year, Smith—daughter of Will and Jada Pinkett Smith and brother of Jaden—hung out in Paris and signed a modeling contract with Chanel. She also released the album ARDIPITHECUS in late 2015.
Cera, on the other hand, is known for boyish actor exploits in films like Juno and Superbad and the acclaimed series Arrested Development, but he's also no stranger to trying his hand at music. In September 2014, he released an indie folk album called True That, which you can listen to here.