Jessica Alba -- actress/entrepreneur
Investments: Headspace, Managed by Q, Honor
You may have heard about Alba's own billion-dollar venture, The Honest Company, which she co-founded in 2011, but she's also a financial backer of a few others including Managed By Q, which is basically a TaskRabbit for office managers. Unclear whether James Bond is involved.
Dwyane Wade -- athlete
The Chicago Bulls star has stake in the novelty sock brand Stance. He's probably just in it for the free socks.
Lady Gaga -- musician
Gaga's big investment was in a venture that would help brands build standalone social networks, but much like Gaga herself, it was reinvented into something slightly different: a way for anyone to create custom-themed online communities.
Justin Bieber -- musician
Investments: Shots Studios, Stamped
If Bieber's star ever burns out, he might be able to live comfortably off the dividends from a pair of investments, including Stamped, a "recommendation" app that was acquired by Yahoo.