So who's going to guest star on the remaining Season One episodes of TMNT on Nickelodeon? Behold the return of the Corey, Kelly Hu, Cassandra Peterson, and Rosanne Barr as the Kraang Prime?! Yes you read that right.
Source: Exclusive: Teenage Mutant Ninja Turtles Guest Cast Includes Roseanne Barr
New episodes of TMNT return on January 25th at a special time before returning to it's usual Saturday morning timeslot. Kelly Hu will be voicing Karai, a character who has played a key role in the TMNT universe in the past. The character will debut in the Febuary 2nd episode "A New Girl in Town". TV Guide actually has a picture of the new character sparring with Leonardo:
Cassandra Patterson, best known for her horror hosting persona, Elvira, will be voicing a character, in the episode following Hu's on February 9, entitled "The Alien Agenda," where she'll be playing a character who takes a special interest in April O'Neil (voiced by Mae Whitman).
As for Corey Feldman, not much is known on the role he'll be voicing. The only information that is known is the character will be appearing in S2 and it'll be a recurring role, and one that'll impact Raphael (voiced by his Goonies' co-star Sean Austin). That sounds suspiciously like it might be Casey Jones, as it was confirmed by the showrunners that the character would be debuting on the show during that season.
Then there's Rosanne Barr as the Kraang Prime. No I am not making this up she will appear on the show. She'll be voicing the leader of all Kraang's (who have been a hive mind so this suggests she'll be literally the Kraang's Queen). She'll be showing up for the season finale which is currently unknown when it'll air (probably if Nick continues running new episodes from the return date, possibly in April).