Lady Gaga, Katy Perry, Justin Theroux and more celebs were quick to hop on social media, posting to Facebook, Twitter and Snapchat to express their outrage at Donald Trump's being elected the 45th President of the United States.

Mother Monster protested outside New York City’s Trump Tower after Trump’s shocking upset in this year’s presidential election.

The “Perfect Illusion” singer, who was big supporter of Hillary Clinton, took to Trump’s building early on Wednesday morning. The 30-year-old, who rocked a black pantsuit, wanted her Little Monsters to know that she still stands with HRC. In the photo, Gaga stood outside Trump Tower on a truck, holding a sign that read, “Love trumps hate.” We hope so, Gaga!

Meanwhile, Katy Perry is clearly reeling from Trump's win -- but trying to "rise" above the unsettling news. The "Roar" singer posted a series of tweets urging her fans to get into action and not let the country be led by hate.

Check out KP's motivational tweets and some of the other celebs who are less-than thrilled about President-Elect Trump: