The Addams Family, The Wicked Witch Of The West and Dorothy from The Wizard Of Oz... Amanda Holden, Vanessa Feltz and Holly Willoughby lead the UK stars undergoing Halloween transformations

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The UK stars kicked off Halloween in style on Thursday, with a legion of stars dazzling in spooky costumes before the clock even struck 12pm. 

Leading the way were Heart Radio hosts Amanda Holden, Jamie Theakston and Ashley Roberts, who transformed into The Addams Family, Vanessa Feltz who became the Wicked Witch and Holly Willoughby who joined her This Morning co-star Phillip Schofield in replicating The Wizard Of Oz. 

Amanda, 48, transformed into Morticia Addams from The Addams Family as she posed alongside her Heart Breakfast radio co-host Jamie Theakston, who dressed up as Lurch from the iconic horror series.

Amanda and Jamie were joined by Ashley Roberts, who also stayed in theme as she channelled Wednesday Addams for the spooky holiday. Amanda looked sensational in character as she clad her slender figure in a tight latex fishtail dress complete with a sleek long black wig. 

Demi Rose set pulses racing as she transformed into a very sexy she-Devil for Halloween. The model, 24, showcased her ample assets as she posed braless with her decolletage covered in fiery red paint and sequins.

Holly looked incredible in her Dorothy costume while Phil was right behind her in an extremely convincing Scarecrow costume - in a move which delighted devoted viewers.  

The TV presenter, 38, bared a striking likeness to the main character, Dorothy Gale, as she donned a pretty blue plaid pinafore dress over a white puff sleeve blouse. She teamed her costume with a pair of Dorothy's famous sparkling red heels, which she paired with some blue ankle socks as she skipped around the studio set. 

Holly, who has previously sported brunette locks despite being known for her blonde tresses, returned to her old look by donning a plaited brunette wig. The Celebrity Juice panellist added to her look with dainty blue bow tied at the end of each plait, while opting for a rosy pallet of make-up.

Phil, who revealed he had been in the make-up chair since 4am, sported a full face of prosthetics to transform him into one of Dorothy's companions, The Scarecrow. The host was given sunken features and was covered in green face paint with a brown nose, while giving the appearance of a stuffed body with handfuls of hay.

Vanessa Feltz looked sensational in a VERY convincing witch costume.  

Vicky Pattison was flying the flag for the reality stars, as she joined a legion of fellow TV personalities at Essex hotspot Sheesh in Chigwell where she transformed into a unicorn while joined by her beau Ercan Ramadan. 

Rebekah Vardy also shared a snap of her family Halloween costume amid her so-called 'WAG war' with Coleen Rooney, as she, husband Jamie and three of their children also dressed up as the Addams Family.

Across the pond, naturally stars were getting in the swing of things as Sofia Richie and Jennifer Garner were representing Hollywood during Halloween. One person who basically 'won the internet' was Kevin Hart, who dressed as The Rock, with a full head of hair and a tight T-shirt as he borrowed his 90s sense of style. 

Sofia went for a fairytale vibe in her pink costume, complete with tiara, sharing her look on Instagram stories over night. And Jennifer, 47, urged the Class of 2019 at her alma mater Denison University to 'go funny over sexy' when it comes to Halloween costumes.

In the commencement speech she gave back in May, the actress, 47, asked: 'Why would you dress like a flirty nurse when you could be a mailbox?' She lived up to her own advice Wednesday when she shared a video to Instagram in which she's dressed up as - yes - a mailbox.

'Live your truth, people. Happy Halloween,' Garner wrote in the caption.

Jason Momoa channeled Elvis Presley himself on the Halloween episode of Ellen on Thursday. The 40-year-old Aquaman star walked out through the crowd in an epic pink Elvis jumpsuit, even giving a costumed fan a lei.

He even tried to mimic Presley's iconic, 'Thank you, thank you very much,' while admitting to Ellen that he's 'obsessed' with The King of Rock and Roll. 

Lupita Nyong'o captivated and terrified audiences with her portrayal of Red in Jordan Peele's Us.

And some fans got to experience it up close. 

For Universal Studios' Halloween Horror Nights (UHHN) she got back into costume and took her place in the Us themed maze. 

Ariana Grande is sure to inspire plenty of costume fodder this Halloween, with her epic looks in her 7 Rings and Don't Call Me Angel videos.  

On Monday evening, Jordyn Woods posed in a beautiful gold and white Cleopatra outfit that showed off her curves after she lost nearly 50lbs last year.

'I found my black queen Cleopatra,' the former best friend and roommate of Kylie Jenner said in her caption.

Kylie Jenner has already modeled multiple costumes this week - with Wednesday's installment seeing the stunner transform into Ariel from the 1989 Disney animated classic The Little Mermaid. 

Doing a rather saucy spin on the doe-eyed character, the cosmetics billionaire, 22, sizzled in an eye-popping shell bra with a slashed tail while donning a sleek red wig which cascaded over her ample cleavage to perfection. 

Her midriff-baring outfit included the purple seashell bra, green tail and long shocking scarlet hair worn by Ariel in the movie. 

The 1989 version starred Jodi Benson as the voice of Ariel, and Disney has cast Halle Bailey in the part for an upcoming live-action remake.

Only a day earlier Kylie and her buddy Anastasia Karanikolaou wore matching Playboy bunny costumes for a Halloween party, as seen on their Instagram pages.

Kylie's Ariel look comes less than a month after she posted social media footage of herself showing The Little Mermaid to her one-year-old daughter Stormi.

The lip kit mogul shares her baby girl with her 28-year-old rapper ex-boyfriend Travis Scott, whom she has tweeted she is 'on great terms' with despite the split.

Meanwhile, Karrueche Tran's latest transformation was into Sin City bombshell Nancy Callahan, as she attended a Halloween bash at Highlight Room in Los Angeles.

The Honour List star, 31, oozed sex appeal as she channeled the stripper in a leather bondage-style bra, which flaunted her washboard abs as she posed for snaps.

Halsey paid tribute to Marilyn Manson from his Mechanical Animals record cover and wore a red wig and blue eyeshadow, as well as a latex white ensemble.