Susan Cagle has gone from busking in the New York City subwaybusking in the New York City subway to inking a major-label recording deal, being named an MTV "You Hear It First" artistMTV "You Hear It First" artist, appearing live on the 2006 Video Music Awards2006 Video Music Awards and relocating to Los Angeles to work on her first studio album — all in the course of roughly one year.

Yet, despite that whirlwind of change, nothing could have prepared her for her Thursday morning (May 10) appointment with Oprah Winfrey.

"It's been pretty amazing, because one of the first shows I did was [on] MTV, and then I just appeared on 'Oprah,' which are both these mega things," she laughed. "So at the beginning of my career, I couldn't ask for any bigger things. It's incredibly exciting and, honestly, mind-blowing."

Cagle spoke to MTV News from her Chicago hotel just minutes after wrapping a performance and interview on an "Oprah Winfrey Show" program largely dedicated to her remarkable rise to fame. The tagline for the episode was "Discovered in a Subway: Now Her Dream Comes True," and it couldn't be more, well, spot-on. Almost a decade ago, Cagle dreamed about meeting Oprah, and she'd be lying if she said she ever thought that dream would come true.

"I wrote a letter in my diary to Oprah when I was 17 or 18, during a very lonely time in my life," Cagle said. "I felt trapped; this whole world inside of me wanted to come out, but I didn't know how to make it happen. And Oprah was an inspiration to me. I never dreamed she'd read my letter. But writing it helped me. I felt like I was venting to someone that I didn't have in my life.

"Then, last year, when [producer] Jay [Levine] and I were writing songs for my new record, we took the contents of that letter and decided to turn them into a song," she continued. "Like I said, I had no idea what would happen, because the lyrics were just taken from my letter to Oprah. And I never thought she, or anyone, would hear them."

But Cagle started playing the song — which she simply called "Dear Oprah" — during some of her subway sets, and it immediately struck a chord with listeners. As luck would have it, MTV News was there to tape one of those performances — watch Susan Cagle performing "Dear Oprah" in the NYC subway right here — and through serendipity (or some aggressive Googling at Harpo Studios), Winfrey came across the clip and instantly reached out to Cagle.

"I got off the plane from L.A. and I had a million messages from people telling me, 'Oprah saw the video on MTV of you singing [the song] and she loved it,' " Cagle said. "And she contacted my producers about getting me on the show to perform the song."

So fast-forward to Thursday morning, with Cagle and her band standing backstage at Harpo, watching stagehands scramble to assemble her equipment for a live performance. The minutes counted down, and then she was face-to-face with her idol — singing lyrics like, "I'm broken, got a problem and my world is crashing down/ I'm writing with the hope that this letter will be found/ Don't expect you to read it, probably got better things to do/ I got no one to turn to, so I'm turning to you."

To say it was emotional was probably the understatement of the year.

"All of a sudden, a producer is grabbing me, going, 'Come up to the stage.' I grabbed my guitar, and Oprah introduces me, and I could barely sing properly, because everyone was crying," Cagle said. "Oprah was sitting in the front row and she was getting emotional, and so were people in the audience. And I kept looking down at Oprah, and she's looking at me with these watery eyes, so I got really emotional too. It was amazing."

After a performance that, according to Cagle, "flew by," she sat down for an interview with Winfrey, who asked her about her childhood and fledgling career. And then it was all over, with Cagle heading back to her hotel room and then on to L.A. to complete work on her album, which is tentatively due in August. And whatever may come for Cagle, she says that it will probably all pale in comparison to this heady Thursday morning, when something that started as an entry in her journal finally blossomed into a full-blown "dream come true."

And, when you think of it that way, can you blame her?

"A lot of people say that Oprah is their role model, and it's sort of this cliché, but it's true. What I like about her is her background, how she came from a turbulent family, was sort of scattered in her 20s, worked really hard and finally became Oprah," Cagle explained. "She just became the best, without having a good background. She built everything up from scratch. And the parallels between her life and mine are obvious. So hopefully I can build something like she has."