Kevin Liverpool and Junior Bradshaw are charged with conspiring to murder and conspiring to rob after prosecutors said they drove from Manchester to Stone's home in Devon in June 2011 with the intent of robbing and killing her, prosecutors said. The plan was thwarted by an "eagle-eyed" resident who became suspicious of the car they were driving and called police, prosecutor Simon Morgan said.
Morgan said others were involved in the conspiracy, as well, but are being tried separately.
Stone, famous for her hit tune "Fell in Love With a Boy," is an "extremely wealthy young woman," Morgan said.
"They got a car, they collected their weapons of choice and they made their way from Manchester to a short distance from Joss Stone's house," Morgan said.
Stone was home at the time, The Mirror said Monday.
The trial is expected to last three weeks.