Pop star Ashlee Simpson has been forced to scrap her appearance at Monday's (19DEC05) Radio Music Awards in Las Vegas, Nevada after collapsing during a show in Japan yesterday (15DEC05).

The singer passed out in a backstage elevator after an MTV Japan performance in Tokyo, and is currently recovering in a nearby hospital.

She had just performed her hit BOYFRIEND on the show when she told fans she wasn't feeling well, and left the stage.

Simpson's publicist has confirmed the incident, insisting the 21-year-old is expected to be fine and is planning on returning home for Christmas.

Sources close to the singer claim she has been suffering from exhaustion.