AceShowbiz -

Keeping a balance between his comedic and dramatic roles, Robert Downey Jr. is coming onboard alongside Jay Baruchel to star in "Tropic Thunder", a comedic feature which marks Ben Stiller's return to feature directing field after his 2001 work of "Zoolander."

Slated to enter production July this year under DreamWorks SKG banner, the project revolves around five actors who find out that everything goes wrong during the making of a big-budget war movie and end up being the commandos they are portraying. Downey Jr. will play a four-time Oscar winner named Kirk Lazarus while Baruchel is billed as Kevin Sandusky, an unknown actor on the set.

Stiller is also penning the script and taking a role together with Justin Theroux as well as seat as the flick's producer. Helping him in doing the former task is Etan Cohen, who recently wrote "Idiocracy" screenplay for the 20th Century Fox.