Katy Perry is determined to encourage young people to vote Hillary Clinton into the White House.

Students at the University of Nevada, Las Vegas, got an unexpected knock on their doors from the singer, who was roaming the halls and drumming up support for the Democratic hopeful on the first day of early voting in the state.

Singer Katy Perry canvasses for Democratic presidential nominee Hillary Clinton in a dorm at the University of Nevada
(John Locher/AP)

The singer was met with squeals and requests for selfies from the students.

She sported bright red lipstick that matched her high heels and a T-shirt emblazoned with the phrase “Nasty Woman”, which has become a rallying cry for Clinton supporters after Donald Trump uttered it during Wednesday’s presidential debate.

Singer Katy Perry canvasses for Democratic presidential nominee Hillary Clinton in a dorm at the University of Nevada
(John Locher/AP)

“We’re out here campaigning for Hillary Clinton. Ever heard of her?” she told a trio of young women after they invited her and a crowd of reporters into their dorm room.

“Because there’s no other alternative. We need our issues heard, we need our bodies taken care of, we need all that choice.”

Singer Katy Perry canvasses for Democratic presidential nominee Hillary Clinton in a dorm at the University of Nevada
(John Locher/AP)

Katy encouraged one student she met who might have to drop out of the school to stay the course, telling her she’d been through her own troubles after being dropped from record labels three times.

And she told about her own financial problems at 17 when she said she couldn’t buy a bag of crisps without getting an overdraft charge.

Singer Katy Perry speaks at a rally in support of Democratic presidential nominee Hillary Clinton
(John Locher/AP)

Katy followed up the surprise round of canvassing with a short outdoor rally on campus, alongside Nevada Democratic Senate hopeful Catherine Cortez Masto.