Professional troll and bottomfeeding blogger Perez Hilton may well be taking his harassment of Lady Gaga to dangerous new heights -- by actually stalking the 'Applause' singer. Yikes!

Fans of Gaga spotted Hilton in her building and alerted her on Twitter, and Gaga rightfully freaked out. Hilton has been harassing her on Twitter, from personal insults to constant comparisons to Katy Perry, and near hourly updates about the status of 'Applause' on the charts (and it ain't good). As if his cyberbullying wasn't enough, now apparently Hilton (real name Mario Lavandeira) is after Gaga in the flesh.

Uh, creep alert! Check out the horrifying exchange below.

It's unclear what exactly caused the rift between Lavandeira and Mother Monster, whom he used to idolize. However, Little Monsters have noted that after Gaga refused to answer questions about her personal life in an interview with Hilton, he turned on her in a big way, despite it not really being personal -- Gaga's never been known to talk about her personal life to the press.

Here's hoping Hilton leaves Gaga well enough alone -- and that she can stay safe from his harassment. No one deserves that ... especially not from someone who advocates against bullying just to stay relevant.

UPDATE: Hilton released a statement about his public war with Gaga:

"My heart hurts that my former very good friend Lady GaGa, a person I used to call my 'wifey' and traveled the world with, is making very public, untrue allegations about me on Twitter."

"While it is still too painful for me to go into detail about why I chose to no longer make her a part of my life, I will say that I am a critic and not a stalker."

"Any allegation that I am stalking her is utterly false, defamatory and now appears to be putting me in danger."

"I will continue to be a critic - in a way that is not mean or involves name-calling, and I will continue to have an opinion and talk about music and songs, like GaGa's 'Applause'".

"As the suggestion that I pose a danger to GaGa is preposterous, if fans want to send a message of support, they should buy her music instead of sending me death threats."

Gaga responded: