The 2010 contestant was found dead at an address in Douglas, Isle of Man on Thursday (30 July).
Katie has now paid tribute to the star, telling BT.com that she believed there was a “big difference” between ‘Stuart Baggs, The Brand’, which he painted himself as on ‘The Apprentice’, and the real him.
Recalling meeting him on a TV show, she said: “I do remember sitting there thinking he was super-confident. Like, super-confident. And he was very keen on making sure we all knew that he was successful.
“And so maybe when the distance between who you are and what you are is too great, maybe that’s just it I guess. The difference between who I thought he was, probably, and the person he seemed to be showing himself to be – there seemed to be a big difference between those two things.
“So I think he genuinely tried to live Stuart Baggs, The Brand. But I think probably realised he was Stuart Baggs, the not so successful person.”
Writing in her column in The Sun, she added: "Without a family or kids who need you, the media can be a tough industry to work in. Sometimes you need the mundane in life to remind you what matters most is not being seen as successful, but helping the people you love the most to be OK."
Stuart’s cause of death is yet to be confirmed, but police are not treating it as suspicious.
Lord Sugar also paid tribute to the star, calling him “one of the stand out characters” from his show’s history, while fellow ‘Apprentice’ star Luisa Zissman added: “RIP one of my fav ever Apprentice contestants Stuart Baggs "The Brand" he has joined the 27 club. What a tragedy."
His sister also penned an emotional tribute on her Facebook page, describing her brother as "the biggest character" who "will leave the biggest hole behind".