Ashlee Simpson is reportedly out of hospital after her sudden collapse earlier this week.

A representative for the singer, who collapsed after a Christmas concert in Yokohama, Japan, said Simpson was exhausted, and was now back in the US with her family.

Simpson had stopped half way through her set, making the excuse that she was "losing her voice." According to an MTV Japan programming manager, this was a joint decision between the channel, her staff and Simpson herself. The concert is still due to air on December 23 at 9pm.

Although earlier reports state Simpson collapsed in an MTV elevator, MTV.com says Simpson went back to her hotel room before her collapse at around midnight local time.