Thom Evans and girlfriend Jessica Lowndes celebrate Heidi Range's birthday

and

joined Sugababe

at the 30th birthday celebrations on Friday. Hot new couple,

and

, joined the likes of Kate Thornton, Ant McPartlin,

and Nicole Appleton who turned out for

's special day.

and

each sported black outfits, with former rugby player and model

choosing a t-shirt and jeans combination, as well as a leather jacket and

star

opting for a a peplum dress and ankle boots.Canadian actress

accessorised her outfit with a glittering statement necklace.

© Photo: Rex

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Hosted at the Sanctum Soho hotel in London, Heidi's party had an '80s theme that encouraged bold and colourful costumes."Hair done," tweeted Liverpool-born

with a photo of her unusual up-do. "Can you guess who I am? X." Birthday girl

posted several photos on Twitter, showing off her Princess Leia outfit and he sister Hayley's Wonder Woman costume.Former

star

dressed as Superman and Heidi's band mate

acknowledged the theme by going as Hilary Banks from

's '80s TV show,

."It's getting light," tweeted

as her celebrations drew to a close. "The birds are tweeting, had the best time at my party tonight. Good night or good morning tweeties x."

© Photo: Getty Images

,

and

had also joined forces on Thursday night as they attended the F&F A/W 2013 Collection Showcase at Somerset House. Keeping to the evening's black and white theme, Thom and Jessica sported colour-coordinating outfits with the white lapels on Thom's jacket matching the white panel on Jessica's bodycon dress.

opted for a white, short-sleeved dress and black heels, adding a splash of colour with a bright red lipstick.

and

confirmed their relationship back in April by posting photos from their trip to music festival Coachella.

, who announced his separation from long-term girlfriend

in February, caused a stir just before the festival by tweeting a photo of

giving him a kiss on the cheek before

put an end to weeks of speculation by releasing a photo of the couple kissing on Instagram.Since then the couple have stepped out together at numerous events and the handsome rugby star was proud to have his lady on his arm when they attended a gala for luxury motoring company Aston Martin on Wednesday.