Elisa Schmidt - who is a protegee of Robbie Williams' former songwriting partner Guy Chambers - is reported to have had dinner with Grant at Borchardt, a popular celebrity hang-out in the German capital.
And German newspaper Bild reported that the pair then walked hand in hand across the Franzosische Strasse in the centre of the city before they 'took a taxi and shared hot kisses in the back seat'.
Schmidt has been quick to play down the rumours, telling the paper that they had met and become friends when she recently visited London.
'I was in London with Guy to talk about my first album,' she said. 'In the evening, we shared a meal and got to know Hugh Grant.
'Since then we have come to understand one another very well and have become good friends,' Elisa added. 'But there is definitely nothing more than friendship. Now he is in Berlin and invited me to dinner. That is all.'
Grant's previous conquests include actress Elizabeth Hurley - whom he dated for 13 years - and heiress Jemima Khan, although he has reportedly not been in a serious relationship since they split up in 2007.