A blonde Jack Black joined the picket line in Los Angeles to show his support for the Writers Guild of America strike.
Ugly Betty cast members marched outside Raleigh Studios to support the strike, prompted by a row over royalty payments.
Jay Leno stopped by the picket line. His talk show has been off the air since the strike began on 5 November.
Actor Ben Stiller supported writers in Los Angeles.
Actors Robin Williams and David Duchovny joined strikers at the Time Warner Centre in New York.
ER's John Stamos, Maura Tierney and Mekhi Phifer marched outside the Warner Brothers TV studios in Los Angeles.
Friends stars Lisa Kudrow and Matthew Perry supported the strike at Universal Studios...
...as did Desperate Housewives stars Felicity Huffman and Nicollette Sheridan. Their show has now run out of scripts.
Elliot Gould also joined the picket line in LA. The last writers' strike in 1988 lasted 22 weeks.