(CNN) -- Miley Cyrus is engaged to her off-and-on boyfriend of three years, "The Hunger Games" star Liam Hemsworth, a representative for Hemsworth said on Wednesday.
"I'm so happy to be engaged and look forward to a life of happiness with Liam," the 19-year-old Cyrus told People magazine.
The two met when they co-starred in "The Last Song" in 2009. They broke up the next year, then reunited less than a year later.
Hemsworth, 22, proposed on May 31 with a 3.5-carat diamond in 18-karat gold with carved diamond floral motifs in an art nouveau pattern, according to Neil Lane Jewelry in Los Angeles. The center stone dates back to the late 19th century, the store said.
The couple sparked engagement rumors in March after Cyrus was seen wearing a diamond ring on her finger at an Arizona event, but representatives for both denied it.
"She makes me really happy," he said. "When you start (filming), you want to be professional, but when you're filming those scenes with someone and pretending to love them, you're not human if you don't feel something."
Meanwhile, Cyrus expressed gratitude to her supporters Wednesday on Twitter. "thank you for all the love today :)" she tweeted. "i'm happy to share this news with you all. I feel like all my dreams are coming true."
Cyrus is working on a new album, People reported, and Hemsworth is filming "Empire State" in New Orleans. He will also shoot a movie with Harrison Ford and Gary Oldman, called "Paranoia," before working on the next "Hunger Games" installment.
"All I ever hoped for as a daddy was to see my kids reach their dreams," tweeted her father, country singer Billy Ray Cyrus. "To find happiness...peace of mind...and someday know...true love."
Cyrus catapulted to international fame after starring in the "Hannah Montana" television series on the Disney Channel. She has also launched a recording career, selling out venues worldwide, and has appeared in several movies.
Born Destiny Hope Cyrus, she earned the nickname "Smiley" as a child, which was shortened to Miley. In 2008, she legally changed her name to Miley Ray Cyrus.
Cyrus has been the subject of controversy. At 15, she apologized after Vanity Fair magazine published provocative photos of her, saying she was "so embarrassed." At 18, she acknowledged that smoking a bong filled with the herb salvia was "a bad decision" after a video surfaced. And last year, she dealt with fallout after joking that she was a "stoner."
Hemsworth, a native of Melbourne, Australia, started acting in high school, according to an Internet Movie Database biography, and followed his brothers Chris and Luke into show business. He was cast last year in "The Hunger Games," which brought him international fame.
CNN's Carolyn Sung contributed to this report.