The first address - given the theme "just be yourself" - will see diversity programme stars Max Laird from Seven Dwarves, Susan Campbell-Duncan of Beauty And The Beast, My Transsexual Summer's Karen Gayle and acid attack victim Katie Piper from Katie: My Beautiful Friends make a "plea for tolerance".
The second will be fronted by Educating Essex headmaster Vic Goddard and his deputy Stephen Drew.
© PA Images / Matt Crossick/EMPICS Entertainment
© Channel 4
It is the first time since the annual broadcast began in 1993 that viewers will see multiple messages.
"Channel 4's Alternative Christmas Message is a yuletide institution giving voice to different opinions and social attitudes," director of creative diversity Stuart Cosgrove told The Guardian.
"This year the [first] message is collectively authored by people who have all starred in shows which foreground diversity. The message is a plea for tolerance and praises difference in a society that often demands conformity."
Previous stars of the channel's Alternative Christmas Message have included Jamie Oliver, Iranian president Mahmoud Ahmadinejad, a 9/11 survivor and The Simpsons.
The 2010 message was delivered by midwives and medical staff being filmed for One Born Every Minute, while Piper made a first appearance the previous year.
'Just Be Yourself' will air on Christmas Day at 1.55pm on Channel 4, followed by the Educating Essex Christmas message at 4.15pm the same day.
