The incident happened at around 3.30pm on Monday, June 22 in fields behind the allotments in Loughborough Road, Hathern.
The 27-year-old victim was out walking when she became aware of someone behind her. She turned round and noticed a naked man. The victim ran off.
The man is described as:
- between 5'5" and 5'11" tall
- in his early 30s
- of stocky build
- with mousey cropped hair
As the victim was running away she noticed the man started to put on a pair of blue boxer shorts with a chequered band.
PC Charlotte Farrow, who is investigating the incident said:
"Obviously this incident was distressing for the victim and has left her quite shaken.
"We are appealing for anyone who knows the identity of the person responsible to get in touch.
"If you witnessed this incident or was perhaps approached by the man in similar circumstances, we would urge you to get in touch."
Anyone with any information is asked to contact PC 4646 Charlotte Farrow on Leicester (0116) 222 2222, follow the instructions to leave a message for a police officer and when prompted key in the officer's identification number 4646.
Alternatively contact Crimestoppers, which is free and anonymous on 0800 555 111.