Hannah Montana star Miley Cyrus stunned the crowd at a charity concert in Nashville, Tennessee on Sunday by making a surprise appearance alongside country star Jeffrey Steele.

Steele hosted the event in memory of his 13-year-old son Alex, who was killed in an all-terrain quad bike accident last year, to raise money for charity.

And the singer was just as shocked as the crowd when 15-year-old Cyrus appeared on the stage, asking to sing a duet with him, according to People.com.

The pair performed hit track Simple Song, which was originally recorded by Cyrus - and was the only song written by Steel that appeared on his son Alex's Mp3 player when he died.

And after a second duet - a rousing rendition of Steele's Hollywood Girl - the country singer paid tribute to Cyrus, telling the crowd, "Miley might live in Hollywood, but in her heart, she'll always be our Tennessee girl."