Los Ageles: Singer-actress Miley Cyrus was caught on video swearing at a rude fan during her vacation in Costa Rica.

Cyrus was making her way to a helicopter with Australian boyfriend Liam Hemsworth when the couple was stopped by a group of fans eager for autographs and photos, reports a website.

Cyrus graciously posed with the youngsters, but, as the couple tried to move and board the aircraft, one angry fan cried out, 'A****e!'

In video footage of the incident, which has since surfaced online, a stunned Cyrus can be seen whipping around and shouting back, 'What the f**k? Are you for real?', before greeting other waiting fans as she walked over to the chopper.