Conversation so far:
What was T-Pain's album, Epiphany?
Epiphany was T-Pain's second album.
Was T-Pain's second album, Epiphany a success?
The album sold 171,000 records in its first week, reaching number one on the Billboard 200. The record has since sold 819,000 records in the United States.

Question: What artists were featured in the album?
Self-contained rewrite: What artists were featured in T-Pain's second album, Epiphany?