One of the ringleaders behind the Hatton Garden heist has admitted stealing £1m ($1.24m, €1.12m) worth of gems from a London jewellers five years earlier.
Danny Jones, 59, is currently serving a seven-year prison sentence for his role in the infamous £29m safe deposit raid of 2015.
The heist saw the burglars drill through a concrete wall to access the high-security lock-up in central London during the Easter Bank Holiday weekend.
Jones has now admitted involvement in an attempt to break into a safe at Chatila jewellers in Old Bond Street, Mayfair, over the August bank holiday weekend in 2010.
The family-owned firm is popular with the rich and famous, including Amal Clooney who wore a pair of Chatila earrings on the day of her marriage to George Clooney.
Jones – who became known as one of the Diamond Wheezers following the Hatton Garden raid – was alleged to have stolen around £1m worth of gems, jewellery and watches from the shop's display cabinets, along with £45,000 in cash.
Attempts were also allegedly made to steal jewellery worth around £40m from a safe.
He answered "guilty" to a charge of burglary at Southwark Crown Court on Friday (17 February). Two others are accused of involvement in the raid.
Terry Perkins, 68, from Enfield, denies one count of burglary, while Charles Matthews, 54, from Virginia Water in Surrey, denies receiving stolen property.
They are both due to stand trial on 27 February at Southwark Crown Court, at the end of which Jones will be sentenced.