Beauty Queen JenPez struts her bountiful #BIGBOOTY; Demi looks a hot mess.

It was Competitor's Pick on Wednesday night's American Idol, but the dress that Jennifer Lopez was wearing was a nice choice too.

The shapely judge stole the attention as she strolled to the studio in Los Angeles before the seven finalists even got underway.

Jennifer, 44, was clad in an ultra clingy, shiny mustard-yellow frock that fit her like a glove and highlighted her most prominent physical asset - her backside.

In front the material covered her all the way up to her neck, but behind a sexy cut-out allowed glimpses of her shoulder blades and lower back where her golden-brown hair fell in expertly styled waves.

The tight skirt trailed to her knees and featured a slight slit in back to allow an easier stride and in those heels she probably needed it.

Jennifer's nude platform pumps probably added a good four inches to her modest 5 ft 5 frame while giving her dancer's calves a workout in the process.

The star was already wearing her microphone attached to the lower rear part of her dress.

Demi Lovato, who was making a guest appearance on Wednesday's show, was also spotted headed to the stage.

The 21-year-old singer was sporting a half-buzzed, blonde-tipped hairdo along with a black leather jacket, black leather trousers and black stilettos with red soles.

The former X Factor judge got to chat about her Neon Lights tour while serving as an unofficial fourth judge in the seat next to Randy Jackson.

Season 13 is down to seven finalists now, and the show allowed them to pick the songs for their competitors.