The former couple are both on the E4 series looking for love.
And it's prompted a fair few awkward moments, not helped by dating agents Nadia Essex and Eden Blackman.
Nadia and Eden set the pair up on a double date that proved particularly uncomfortable for everyone involved.
In tonight's show, Seb and Tallia once again come face to face after Nadia arranges for them to meet up and clear the air.
But what happened between the former young love birds?
Singer Tallia and professional racing driver Seb dated for three months but says it ended in "disaster".
Tallia said: "He's the first ever person I properly opened up to. I let him into my world and I never let anyone into my world.
"And when I see him it's a reminder of my weakness that I actually opened up to someone and it ended in a disaster."
She continued: "This whole thing literally only lasted like three months but the problem was it happened so quickly. I met him and within a week he literally said he was in love with me.
"It was the first time, I don't want to say love, the first time I had a proper crush. He was the first ever one. It was just all so perfect and it almost got too intense.
"It didn't end in a conversation - I just kind of shut it out."
Despite the bad break up, Seb said he was glad to get closure.
"To be fair the only good thing I'll say is I'm glad it's done because I hadn't seen her for a couple of years, so at least now I've seen her," he explained.
Alongside Tallia and Seb, other stars on the show this series include Hollywood's Jonathan Lipnicki, Olympian Jade Jones, comedian London Hughes and TOWIE's Gemma Collins.
They're joined by Made In Chelsea’s Sam Thompson and Ollie Locke, plus Love Island's 'Muggy' Mike Thalassitis.
Celebs Go Dating airs Sunday-Thursdays.
You can tune in each night at 9PM on E4.