Stone, whose hits include "Super Duper Love" and "Fell In Love With A Boy", insisted she was "absolutely fine" after police informed her of the alleged plot.
"I'd like to thank everyone for their concern but I'm absolutely fine and getting on with life as normal while the police continue with their enquiries," said the 24-year-old.
The arrested men had detailed maps and aerial photos of Stone's property, the Sun newspaper reported.
The arrests came after neighbours spotted two men driving slowly around remote country lanes in Cullompton and reported them to police, said the paper.
"Police attended an address in Cullompton yesterday morning after alert residents notified officers about a suspicious-looking vehicle," said a local police spokesman.
"Officers attended the area at around 10:00 am and subsequently arrested the occupants of a red Fiat Punto."
Stone has sold more than 10 million albums worldwide and has worked with music legends including Rolling Stone Mick Jagger and the late US soul superstar James Brown.
She is estimated to have a personal fortune of £9 million (10.2 million euros, $14.7 million), according to a list of Britain's wealthiest people published by the Sunday Times last month.
Stone is a friend of Prince William and attended his wedding to Catherine on April 29.
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