Say it ain't so!
More from YourTango: Who Is Zac Efron's Rumored New Girlfriend Halston Sage?
The pair apparently ended their relationship earlier this month.
This split is fairly shocking, as they had seemed to be doing well recently. The couple had been spotted on vacation in Cancun with William's pal Busy Philipps in January.
In October, the two reportedly bought a Brooklyn loft together, and Matilda—the My Week With Marilyn star's seven-year-old daughter with the late Heath Ledger—was said to be very close with Segel. We've all seen the adorable photos of him putting her on his shoulders!
So, what went down?
Find out why at Wetpaint: Michelle Williams Is Single Again After Split With Jason Segel
More juicy content from Wetpaint:
- Selena Gomez Mocks Justin Bieber's Outfit: I'm "Embarrassed For Him"
- Jennifer Aniston's "Small" Wedding: Rings, Dresses & Date Chosen!
- Is This Marc Anthony's New Girlfriend?
Photo Credit: Getty