A brat.

“CSI’s” Marg Helgenberger, who got her start in Daytime as Siobhan Ryan Novak on “Ryan’s Hope” (1982 to 1986) commented on teen pop idol Justin Bieber’s behavior during his cameo role on the hit CBS show. Apparently, while on the set, Justin punched his fist through a craft services cake.

Marg told French radio show “Le Grand” during an interview, “I probably shouldn’t say this, but he was kind of a brat. He locked one of the producers in a closet and he put his fist through a cake that was on the craft services table.”