It has previously been announced that both Ron Perlman and Selma Blair will appear in the Hellboy sequel. Here is what Del Toro had to say:
John Hurt is back for a cameo.
Myers is not back (see Rupie in KISS OF THE SPIDER WOMAN in the London stage!!).
Universal has NOT authorized a brief Kroenen cameo/ epilogue- yet.
Johann will be played by John Alexander (body) and Tomas Kretschmann (voice).
Dougie will play 4 characters.
Brian Steele will play 4 characters.
Anna Walton is the actress playing Princess Nuala.
Luke Goss plays Prince Nuada. Silverlance.
Roy Dotrice plays King Balor
Filming starts this Friday, June 8 in Budapest. Hellboy 2: The Golden Army will be released on August 1, 2008.