For those who have a PMP or CAPM certification there is a fast track to become PRINCE2 Practitioner. You can directly go for the PRINCE2 practitioner certification without PRINCE2 Foundation certification.
from KnowledgeTrain wrote two nice articles to support this track:
- PRINCE2® and the PMBOK® Guide: a comparison
- A guide to PRINCE2 for PMP® and CAPM® Credential Holders