When Did Penn Badgley & Blake Lively's Relationship Turn Romantic? You'll Never Know!

Penn Badgley comes out to support the Havaianas Limited Edition 2010 Team Sandals Collection launch with GQ at NYC’s Barneys on Thursday (June 10).

The 23-year-old Gossip Girl actor was asked when his relationship with girlfriend Blake Lively transitioned from being professional to personal.

“You know what?” Penn told JustJared.com. “That’s a mystery. I’m not going to let you know that! (laughs) Because nobody knows and I’m gonna leave it that way.”

Smart!