A number of fans have revealed that they believe the pair are dating, even nicknaming the duo "Larry Stylinson".
Tomlinson, who has been dating his girlfriend Eleanor Calder for around a year, took to his Twitter page yesterday to slam the speculation.
"Still months on reading ridiculous conspiracy theories," he said. "It's upsetting that I have to read them daily. Thank god for the lovely people on here."
After some fans questioned whether "management" had taken over his Twitter after Tomlinson blocked some followers, he vowed: "I block people who bad mouth the people I care about" and said: "The only person who has access to my account is me!"
Meanwhile, another fan alleged that the singers would "never deny Larry", prompting Tomlinson to respond: "Hows this , Larry is the biggest load of bulls**t I've ever heard. I'm happy why can't you accept that."
Tomlinson also took exception after his mother received an abusive message on the social networking site, saying: "Can I ask why this is ok? To think someone would speak to my Mum like that sickens me. Grow the f**k up !"
However, Tomlinson also wrote a series of messages thanking his "real" fans for their support.
"Ohh dear I've gone to town today haha," he wrote. "Lots of love to all of you amazing fans !!
"Please know that we love you all so much! We are forever grateful for the success you've helped us achieve!"
He later added: "And now to finish on a good note :) ive clearly flipped on twitter today. I'm sorry to any REAL fan of ours that I've offended. All I've ever wanted to do from day one is please the people who support us. It's hard when people are rude to our families.
"I love all our true fans so f**king much! That's a promise ! I assure you all I'm always true to myself ! #embarrassingtweet"
He went on: "Wouldn't mind a good heart to heart with @zaynmalik right now ! Missing you man !"
Tomlinson has previously complained about the treatment Calder has received on Twitter and has also denied the 'Larry Stylinson' speculation before, saying: "This is a subject that was funny at first but now is actually hard to deal with, as I am in a relationship. Me and Harry are best friends. People look into our every move - it is actually affecting the way me and Harry are in public."