Rumours of McIlroy love split as Wozniacki tweets dry up
The sporting couple regularly use the site to send each other amorous messages, but they have now removed each other from their profile pictures.
Contacting each other publicly has also seemed to have stopped.
The golf ace last sent Ms Wozniacki a message in July, while she last tweeted him a supportive message on August 11.
Asked about the relationship before embarking on his round at the Barclays PGA Tournament in Jersey City yesterday, he said he'd answer questions after his day's play.
'Wozzilroy', as they were affectionately branded have been dating for just over two years.
Rory parted suddenly from his live-in girlfriend and childhood sweetheart Holly Sweeney when he started dating Ms Wozniacki after meeting her at a boxing match in Germany in 2011.
The Co Down native has had a very disappointing season, failing to clinch any major wins.
He is currently competing in New Jersey, while Wozniacki is set to compete in the US Tennis Open next week.
Wozniacki (23) owns an apartment in Monaco and McIlroy has regularly publicly referred to it as 'home'.
This may not be the only split McIlroy will face this year. He recently parted ways with his Irish management team, Horizon Sports Management, after the most successful spell of his life, which saw him win two Majors as well as securing a sponsorship deal with Nike, reportedly worth up to €185m.