The cast of En serio y en broma - 1962 includes: Pedres as himself Francisco Canalejo
The cast of Casi en serio - 1999 includes: Leo Caprile as Himself - Host
The cast of Va en serio - 2006 includes: Carlos Ramos Padilla as Himself - Host
The cast of un sogno serio - 2010 includes: Cesare as himself Ivan Del Prato as Him self
The cast of Un uccello molto serio - 2013 includes: Elena Arvigo Chiara Caselli Rolando Ravello
Manuel del Palacio has written: 'En serio y en broma'
The cast of Isolate - 2012 includes: Stephen Anderton as Richard Jacinta John as Scout Terry Serio as Dad
The cast of Polly and Me - 2009 includes: Madison De Sousa as Girl Emma Palmer as Mum Terry Serio as Boyfriend
The cast of Cocks - 2011 includes: Matilda Brown as Chick Kick Gurry as Alpha Oliver Leimbach as Virgin Terry Serio as Gay
The cast of Great Western - 2012 includes: Matt Doran as Greg Grogan Costas Kilias as Yousef Terry Serio as Chris
The cast of Wall Boy - 2009 includes: Danny Adcock Keegan Joyce Terry Serio Ben Wood as Youth Worker
The cast of InHumane Resources - 2012 includes: Marzio Diaz as Manager Mariasole Michielin Alessandro Serio Isacco Tognon Michela Virago
There are many ways that this can be translated and they depend on what you mean by "I'm serious". If you are say as a description of yourself (I'm a serious person), then it would be "Soy serio" [or seria if you are a girl]. If you are saying it to someone who doesn't believe what you are saying, then you can say "Estoy serio/seria" or "Hablo en serio", both of which mean "I'm serious", though the latter is a better translation. You can also say "No bromeo" which is "I'm not joking".