Celebrities are used to getting all dressed up for parties – it’s part of the job. But one night a year it’s about looking as frightful as you can, and the rich and famous go all out.

Sugar and spice and all things nice – that’s what Holly Willoughby is made of. But not when she attended Jonathan Ross’s Halloween party last year. She was a horrifying zombie!

Holly Willoughby as a zombie
Holly Willoughby (Yui Mok/PA)

And Holly isn’t the only star who likes to do scary on Halloween.

Check out James Franco and Megan Fox.

And Kelly Osbourne’s “hot” date at this party gives us the shivers.

We think Michelle Trachtenberg took more influence from Buffy the Vampire Slayer than Gossip Girl for this outfit.

Michelle Trachtenberg as a zombie
Michelle Trachtenberg (LuMarPhoto/AFF)

Chloe Moretz usually looks cute as a button, but not during the witching hour.

Chloe Moretz as a witch
Chloe Moretz (Yui Mok/PA)

Gwen Stefani has gone for subtle with this discreet bullet hole in her otherwise stylish ensemble.

Gwen Stefani as a zombie
Gwen Stefani (Yui Mok/PA)

And queen of Halloween costume parties Heidi Klum is not afraid to embrace the ageing process after dressing up as a glamorous grandma last year.

Heidi Klum is a glamorous granny for Halloween
Heidi Klum is a glamorous granny (Owen Hoffman/AP)

While some celebs relish in making themselves look scary, others take the chance to hide behind a mask.

You’ll have to take our word for it – but that’s Sacha Baron Cohen and wife Isla Fisher under there.

Sacha Baron Cohen and Isla Fisher in Halloween masks
Sacha Baron Cohen and Isla Fisher (LuMarPhoto/AFF)

We’re guessing that’s Tim Burton in the rabbit mask with wife Helena Bonham Carter.

Helena Bonham Carter and Tim Burton in rabbit mask
Helena Bonham Carter and Tim Burton (Yui Mok/PA)

And this is Breaking Bad star Aaron Paul with his wife Lauren Parsekian.

Aaron Paul in a Ronald Reagan mask
Aaron Paul and wife Lauren Parsekian (Todd Williamson/Invision)

Really, it is!

Aaron Paul
Aaron Paul (Todd Williamson/AP)

David Hasselhoff recently told us he dresses up in a mask of himself on Halloween – and no one hassles him because they don’t think he’s The Hoff.

David Hasselhoff (See Li/Demotix)
David Hasselhoff (See Li/Demotix)

Of course you don’t have to look a fright on Halloween. Iggy Azalea looks fab and ferocious as Cruella De Vil.

Iggy Azaela as Cruella De Vil
Iggy Azaela (Joel Ryan/Invision)

While Fergie has gone for OTT and trashy in this beauty queen get-up.

Fergie
Fergie (Dennis Van Tine/ABACA)

And Kim Kardashian has made the most of those famous curves as a mermaid.

Kim Kardashian as a mermaid
Kim Kardashian (LANDOV)

Of course some women just can’t bear to send themselves up, even on Halloween. But you have to be careful, because there’s a fine line between sexy and slutty.

Paris Hilton as Minnie Mouse
Paris Hilton (LuMarPhoto/AFF)
Daisy Lowe in a bear costume
Daisy Lowe (Yui Mok/PA)