When Louis Tomlinson found out that a 24-year-old stalker had been sending his 15-year-old sister Lottie inappropriate text messages and tweets, he was furious. The One Direction star has always been very protective of his sisters — especially Lottie! — so when she spilled the entire story to him backstage before the band's recent show in Manchester, Louis knew he had to handle the situation himself.

Not only did Louis confront the Internet creep about the scary messages, he also let him know that he better not even think about showing up at 1D's concert!

"Louis wanted to be focused on playing at one of the biggest venues in the country but his sister comes first and he wanted to make sure he was protecting her," a source told Daily Star. "He didn't hold back when he called the bloke. He was really angry about what had been going on."

Lottie ended up taking a short break from Twitter, but now she's back online and seems to be doing fine.

Are you proud of Louis for sticking up for his sister? Are you happy to see that he always puts his family first? Sound off in the comments!