Burridge is trying to beat Chris Maloney, Amy Mottram and Times Red in a public vote to secure a spot on Saturday's programme.
Tomlinson had previously backed Burridge to become the 13th finalist on this year's X Factor on Twitter, but the boyband star went one step further last night.
The 'What Makes You Beautiful' singer was a special guest at the Shoreditch Cornershop venue and cheerleaded for Burridge, regularly chanting, "More! More!" in between songs.
Burridge performed covers of 'You're The One That I Want' and 'Titanium' at the gig, plus one of his own tracks, and a self-penned duet with X Factor finalist James Arthur about their time on the reality show.
Rylan Clark introduced Burridge onto the stage and urged fans to pick up the phone for his co-star, claiming that he was going to become a "global star".
The X Factor wildcard will be revealed at the start of this weekend's first Live Show on Saturday night (October 6).
Watch Adam Burridge's interview with Digital Spy below: