Former Manchester United star Cristiano Ronaldo and his Russian girlfriend Irina Shayk have allegedly broken up.

Rumours that the couple have split started after the 29-year-old supermodel suddenly unfollowed him on Twitter, the Daily Mail reported.

Additionally, Shayk did not come to support the Real Madrid player when he was honoured with the prestigious Ballon d'Or title for the third time at a ceremony held in Zurich, Switzerland.

Ronaldo, who has been dating Shayk since 2010, did not mention her in his acceptance speech as well.

However, a spokeswoman at her New York-based PR company told that Shayk could not attend the event because of previous work commitments: "[The Ballon d'Or] didn't fit in with her schedule - it was because of work commitments. We have no further comment to make."

In 2013, during an interview with Gazeta Sporturilor, a Romanian sports newspaper, Shayk gushed about Ronaldo.

"I feel proud and very happy that I am with him. Cristiano is a great guy with whom I get along very well. But often, he is with the team, I'm at events or photo shoots, but we talk a lot!" she said.

Ronaldo and Shayk's relationship has seen some highs and lows.

In 2013 April, Andressa Urach, Miss Bumbum Brazil 2012 runner-up, claimed that Ronaldo had sex with her 48 hours before a Champions League semi final.

However, he took to Facebook to deny reports that he cheated on Shayk.