Nicole Richie's hair catches fire as she blows out candles during 40th birthday party

Reality star Nicole Richie accidentally set her hair on fire during festivities to celebrate her 40th birthday.

The television personality and designer had been marking her big day with an outdoor party surrounded by family and friends when the incident took place.

A video shared by Richie on Instagram showed her hair catching fire as she leaned over to blow out the candles on her birthday cake - before she was given help to put out the flames.

She joked on Instagram: "Well... so far 40 is (fire emoji).

Her husband Joel Madden also saw the funny side, as he adopted a catchphrase used by Richie's close friend Paris Hilton when he commented: "That's hot."

She married the Good Charlotte lead singer at her father Lionel Richie's home on 11 December 2010.

They share a daughter, Harlow, born in January 2008 and a son, Sparrow, born September 2009.

Hilton also commented: "OMFG Happy Birthday Bill! Hope your ok! Love youuuuu".

Madden's twin brother and lead guitarist of Good Charlotte, Benji Madden, added: "Happy Birthday Sis love you and thankful for you always, stay lit", with a heart, celebration and fire emoji.

Singer and Destiny's Child star, Kelly Rowland, also wrote: "My heart just dropped!!!!"

While her hairstylist, Gregory Russell, was clearly alarmed and commented: "STOP!!! AGAIN?!?!", to which Richie replied: "I'll start a Pinterest board for new haircuts. Start thinking of cute curly bobs."

Richie first came to prominence when she appeared in the American reality TV series, The Simple Life, which ended in 2007.