Geraldine Winner was hit on the head and forced to hand over her jewellery in the frightening incident on Friday, reported BBC online.
The two thieves - a man and woman - are alleged to have broken into the 4 million pounds penthouse in west London after hiding in one of the building's communal gardens.
A Metropolitan Police spokesman confirmed that an investigation has been started in a bid to track down the culprits, adding, "Nobody has been arrested at present and the investigation is ongoing."
