With his shaggy locks tied back for a workout, Efron leaves his Beverly Hills gym. Plus: Tori Spelling, Nicole Richie, Matthew McConaughey and more.

JUST DUET

Call them the karaoke kings! Step Brothers costars Will Ferrell and John C. Reilly show off their vocal prowess with the Dolly Parton-Kenny Rogers classic "Islands in the Stream" (with Ferrell handling Kenny duties) Tuesday on their visit to MTV's TRL studios in New York. Their comedy hits theaters July 25.