A woman has been left feeling “very relieved and excited” after firefighters dived into a river to retrieve her huge diamond ring after it fell overboard.

During a trip on a yacht along the Charles River in Massachusetts, US, the woman dropped the impressive piece of jewellery into the water below.

The dive team from the local fire department was alerted to the incident while working on another job along the waterway and came to help.

Luckily, the “distraught” owner, and her husband, had a good idea about where the ring had landed and the divers were able to recover it in less than five minutes.

“The ring was returned to its very relieved and excited owner and the crew members secured the equipment for the rest of the detail,” Cambridge Massachusetts Fire Department said.

“This is an amazing example of using our training for public service and a terrific opportunity for the dive and marine unite members to practice working together.”

A day after the incident, the woman contacted the fire service to say thank you for their efforts.