Kiss Kiss Bang Bang (2005) on Netflix

In Los Angeles, whilst being chased by police officers, thief Harry Lockhart finds himself in a movie audition where he is mistaken for a actor, auditioning for a role in a detective film. Harry attends a party where he reunites with childhood friend Harmony Faith Lane, who is acting in Beer commercials and wants to make it to the big time and act in Hollywood movies and Harry also meets gay private detective Perry Van Shrike. When Perry discovers a dead body and Harmony's sister commits suicide, Perry decides to involve Harry in the investigation and Harry decides to play along and pretend he is a detective. Investigating the case, Harry and Perry become suspicious of the party guests who have all become suspects, as Harry and Perry set out to uncover the murderer's identity, Harry finds himself falling in love with Harmony.