Leanne Bloomfield, 29, denied using a shard of glass to cut Natalie Walsh, 22, upwards from her neck to her chin at Cafe De Paris in London's West End in February last year.
But a jury found the mother-of-two guilty of wounding with intent following a four-day trial last month.
She was sentenced to five years at Southwark Crown Court in London today after Judge Peter Susman QC told her: 'Quite why your attack on her was so violent remains unclear to me.'
