The pair were seen spending £500 at exclusive store Petit Tresor, although a source close to them claimed that the purchases were for a friend.
Reeves is thought to have been dating the Superman Returns star since April.
"They both looked really happy. They were holding hands and laughing as they walked around the shop. Keanu was picking out lots of different things and seemed really excited," said an onlooker.
Reeves was linked to The Private Lives Of Pippa Lee co-star Winona Ryder earlier this year.
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