U.S. pop star Kelly Clarkson announces engagement

Kelly Clarkson performs a medley of songs at the 40th American Music Awards in Los Angeles, California, November 18, 2012.

LOS ANGELES (Reuters) - Kelly Clarkson, who became the first contestant to win "American Idol" a decade ago and went on to several chart-topping successes, has gotten engaged to her boyfriend, the singer said in a Twitter message on Saturday.

Clarkson, 30, previously revealed she had been dating talent manager Brandon Blackstock since early this year. Blackstock is the stepson of country singer Reba McEntire.

"I'M ENGAGED!" Clarkson said on Twitter. "I wanted y'all to know!! Happiest night of my life last night!"

She then followed that by posting a link to a photo of her canary yellow diamond engagement ring on a website. She wrote that her boyfriend helped design it and that she "can't wait to make Brandon's ring."

Clarkson's album "Stronger" hit No. 2 last year on the Billboard 200 sales chart, and she in previous years topped pop charts with her songs "My Life Would Suck Without You" and "A Moment Like This."

The Texas-born singer won the Fox television singing contest "American Idol" in the show's debut year in 2002, and has had more success than many of the show's stars from following years.

Clarkson has burnished an image as an artist willing to speak her mind, even confessing to feelings of loneliness.

Last month, in an appearance on the "Ellen DeGeneres Show," Clarkson said she had been dating Blackstock since earlier this year and was thankful to have him.

"I am not alone for the first time for Thanksgiving and Christmas and I'm very happy," she said on the show.

In the same November appearance, Clarkson said she expected to get engaged to Blackstock. "We will totally, probably elope," she told DeGeneres.

(Reporting By Alex Dobuzinskis; Editing by David Bailey)