Demi Lovato has long been open about her own struggles with the bipolar disorder she was diagnosed with four years ago, and this week she's taken her mental health advocacy all the way to Washington, D.C. Yesterday (October 5) the "Confident" singer joined the National Council for Behavioral Health's Hill Day, a two-day event in which healthcare professionals, advocates and members of Congress discuss improving mental health resources.

"When I got diagnosed, it was a relief to know that I wasn't just being ungrateful, that it was actually me being sick," Demi told U.S. News during her visit to D.C. Demi announced her own campaign for mental health awareness and destigmatization, Be Vocal: Speak Up for Mental Health, back in May. On Capitol Hill, the pop star seeks to urge legislators to provide more affordable care for those struggling with mental illness. "I remember going to treatment and there were girls that would … be there for a week and then their insurance would stop paying," she explained. "That's a problem."

Republican Senator John Cornyn praised Demi for her efforts — and snapped a photo with the singer, who wore an edgy-for-Capitol-Hill red dress — saying in a Tweet, "Congratulations to for using her celebrity to advance the treatment of mental illness."

Equally impressive was Demi's appearance on MSNBC on Monday, where she discussed her cause with host Tamron Hall. She said she was advocating not just for young people, but for older folks as well, because it's an ongoing process. "It actually takes about 10 years for someone to be properly diagnosed and find the right treatment while suffering with bipolar disorder or mental health illnesses. What I'd love to see is comprehensive mental health reform in our government." How many pop stars have held their own on a news show? You can watch the full interview below, and check out her Be Vocal site here.

Demi Lovato's Most Inspirational Speeches