The former N-Dubz star's debut track 'Young' leads this week's chart update, pushing Carly Rae Jepsen's 'Call Me Maybe' down to number two.
Cover Drive are at number three with their latest single 'Sparks', while fun.'s 'We Are Young' is at four and Alex Clare's 'Too Close' is at five.
Marina and the Diamonds is at 10 with 'Primadonna', Sub Focus and Alice Gold are at 18 with 'Out Of The Blue' and Lana Del Rey's 'Blue Jeans' reaches a new peak of 28.
Further down the chart James Vincent McMorrow's 'Higher Love' climbs 133 places to 29 following Tyler Vincent's rendition of the song on The Voice, while Beyoncé's 'Listen' is at 36 after Malaki Paul's audition on Britain's Got Talent.
Over on the album chart Marina and the Diamonds is on course to claim her first UK number one album with Electra Heart.
Lana Del Rey moves up to two with her debut effort Born To Die, Jack White's Blunderbuss falls to three, Norah Jones lands at four with Little Broken Hearts, and Adele's 21 is at five.
> View the current singles top 100 here
Watch the music video for Tulisa's 'Young' below: