Fans of Harry Styles and Louis Tomlinson took over Twitter Monday - but they weren't your average One Direction fans tweeting. These fans are avid believers of "Larry Stylinson," or a secret Harry Styles and Louis Tomlinson relationship. With the help of these One Direction shippers, the hashtag "#WhyIBelieveInLarry" was trending worldwide on Twitter.

Fans of "Larry Stylinson" tweeted their reasoning for Harry Styles and Louis Tomlinson's secret coupling, with explanations such as the ones below:

Because "just friends" don't look at each other like that. #WhyIBelieveInLarry pic.twitter.com/fyMJpPZTCy

— Larry Stylinson (@harry69s_louis) February 9, 2015

#WhyIBelieveInLarry they have a full love story written in pictures and quotes on their arms pic.twitter.com/iyABhS9vpm — Liam Payne (@Liam_OopsHi) February 9, 2015

#WhyIBelieveInLarry BECAUSE HARRY'S FACE LIGHTS UP LIKE THE ACTUAL SUNSHINE WHENEVER HE LOOKS AT LOUIS pic.twitter.com/GznJwdzAdL

— neil (@niallsayswhaat) February 9, 2015

When someone asks you why you believe in Larry: #WhyIBelieveInLarry pic.twitter.com/TPEM5N9Rwx — Zayn-man. (@_kidrauhlft1D) February 9, 2015

As we previously reported, fans of "Larry Stylinson" melted when they found out that the One Direction bandmates were caught traveling together for the first time in three years.

According to Yahoo! UK, Harry Styles and Louis Tomlinson had been enjoying some quiet time in Los Angeles together following Harry's 21st birthday party on Saturday, and Thursday night they were both spotted jetting out from LAX to Australia ahead of One Direction's opening night for their "On The Road Again" tour on Saturday. This is the first time they've been seen traveling together since 2012.

Louis Tomlinson is very stealthy when it comes to traveling - he's rarely spotted on the go and spent most of his time in Los Angeles without being seen.

But things changed Thursday: not only did he travel with Harry, but he also made his entrance to Australia very public, happily posing for pictures with fans as he and Harry Styles made their way through check in.

One explanation for not traveling together is to stave off "Larry Stylinson" gossip. It's no secret that many One Direction fans speculate that Louis Tomlinson and Harry Styles have the hots for each other, with some even claiming that Louis' girlfriend Eleanor Calder is his "beard" to cover up his relationship with his bandmate.