UPDATE: Watch Lady Gaga blast Trump and perform at Joe Biden's Pittsburgh rally.

Lady Gaga has thrown her support behind the Joe Biden campaign, and will be performing at an election-eve rally in Pennsylvania, which has emerged as a key state that the entire election could hinge upon. Pittsburgh City Paper reports that Gaga will join Biden at his final Pittsburgh stop in the state, performing two songs at what's expected to be a drive-in event. John Legend will appear with Kamala Harris in Philadelphia, and that will air on C-SPAN at 8:10 PM ET.

"Good morning PENNSYLVANIA!," Gaga tweeted on Monday. "I’m so excited to see you today and SING for you!!!!!!! I believe in YOU & I !! Let’s talk about what America looks like with a KINDER President. WE NEED EVERY VOTE. I’m with @JoeBiden — Lets go 24 hrs!!!!!! #Biden #AmericaNeedsPennsylvania"

Earlier, Gaga tweeted that she was "SO EXCITED to be back in Pennsylvania! (Pittsburgh where I used to fly into to visit my grandma!). See you tomorrow at Joe’s rally! WE NEED EVERY VOTE PA - make a plan. This election depends on you. #Biden #vote"

She also shared a picture of herself from when she lived in Lancaster, and one of her with Biden:

Meanwhile, the Trump campaign issued a press release on Sunday (11/1), criticizing Biden for campaigning alongside Gaga, who is against fracking, a key issue in PA. "Nothing exposes Joe Biden's disdain for the forgotten working men and women of Pennsylvania like campaigning with anti-fracking activist Lady Gaga," Trump 2020 communications director Tim Murtaugh wrote in the release. "This desperate effort to drum up enthusiasm for his lackluster candidacy is actually a sharp stick in the eye for 600,000 Pennsylvanians who work in the fracking industry. Biden repeated promised left-wing activists he would end fracking, which would be an economic death sentence and financial Armageddon for families in Pennsylvania and across the country. A big reason the Pittsburgh Post-Gazette endorsed President Trump is because he supports and defends American energy workers and is the best candidate to make our economy great again. Joe Biden will always prioritize the desires of the liberal Hollywood elite and the radical left, while President Trump will always put the interests of blue-collar workers first."

Gaga responded to the release on Twitter, writing, "HEY TIM HEY @realDonaldTrump SO HAPPY IM GLAD TO BE LIVING RENT FREE in your HEAD. #BidenHarris"

UPDATE: Watch Lady Gaga blast Trump and perform at Joe Biden's Pittsburgh rally.