Jay headed to London clubbing hotspot, Mahiki, on Wednesday (24 July) to party until the early hours and emerged from the nightclub afterwards looking a little worse for wear, as he appeared to be being propped up on the shoulder of a friend.
Sign of a good birthday then?
The curly haired pop star kept his outfit ultra casual and given the hot weather, donned a pair of shorts to dance the night away in, as well as some Converse trainers and a navy blue shirt.
Joining Jay for his celebrations were a number of other celebrity guests, including his bandmate Tom Parker and TOWIE's James 'Arg' Argent!
Arg also sported a laid-back look for the evening and opted for a simple navy sweatshirt with jeans and loafers.
Noticeably absent from the reality TV star's side were his TOWIE cast-mates, who he is often seen out and about with, and his new BFF Helen Flanagan wasn't there either.
However, there was no shortage of fashionable females on the night, as Ashley Roberts and Laura Whitmore came up trumps for the girls in their cute clubbing outfits.
While Pussycat Doll Ashley went for a chic black skater skirt and white vest combination, Laura sported a pretty light blue summer dress, which she accessorised with contrasting red heels.
The two girls also styled their blonde locks in different ways, with Ashley opting for a high top knot and Laura going super sleek and straight.
During the day, Jay jokingly tweeted about his birthday by writing: "I've gone round the sun 23 times!!!"
He also appeared to be taking some time out from The Wanted's busy schedule by hanging out with his mum and his brother and indulging in some super strong lager, which he dubbed "The drink of KINGS!!"
Sounds like he had a great time!
Which girl's outfit do you prefer - Laura or Ashley's? Let us know below, as the best comment from across the website each week wins £50!
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Copyright: WENN Craig Harris