The lighting designer admitted to pocketing an advance of thousands of pounds paid by an Antiques Roadshow expert Rupert Maas.
Coombs conned Maas out of £3,500 by promising to deliver low-energy LED lighting to Maas’ Mayfair gallery in 2010, then making off with the payment.
Dressed in a grey suit, white shirt and black tie, Coombs spoke only to enter his guilty plea to a single count of fraud during the brief hearing.
The lighting designer was originally accused of defrauding a number of top London art galleries of sums amounting to almost £20,000, but prosecutors today asked for the other fraud charges to lie on file.
Coombs allegedly tricked David Dallas out of £12,600 after promising to supply lighting schemes in September 2009. Dallas worked for Johnny van Haeften, which runs a central London gallery in Duke Street specialising in Dutch and Flemish Old Master Paintings of the 16th and 17th centuries.
The designer was also alleged to have used to same ploy to convince art dealers Stoppenbach & Delestre to part with £3,400 in November 2009.
Coombs, with an address in Weybridge, Surrey, was remanded on bail and will be sentenced on 20 April.