When the first "Pirates of the Caribbean" movie was first announced in 2002 most moviegoers wouldn't have recognized any of the cast besides Johnny Depp and Geoffrey Rush.  Back then Keira Knightley and Orlando Bloom were hardly household names. So, with producer Jerry Bruckheimer and Depp having promised "Pirates of the Caribbean: On Stranger Tides" would begin a whole new arc for Captain Jack Sparrow, it's not surprising more relative unknowns are jumping on board the Black Pearl this time around.

The latest to join "Tides'" journey to the fountain of youth is Sam Clafin.  Walt Disney studios says the 23-year-old Brit will play the key role of Philip, a youthful missionary.  He's the second casting announcement this week after the studio revealed on Wednesday that French actress Astrid Berges-Frisbey would play the beautiful and alluring mermaid Syrena in the sequel.

Clafin credits include the upcoming Starz mini-series "The Pillars of Earth" and the UK TV movie "The Lost Future."

Besides Depp, Clafin and Berges-Frisbey will join veterans Penelope Cruz and Ian MacShane when "Tides" begins production in Hawaii this June.

"Pirates of the Caribbean: On Stranger Tides" will open nationwide on May 20, 2011.