Oliver Mellor has reportedly "warned" Cristiano Ronaldo to stay away from his fianceé Rhian Sugden.

According to The Sun, 36-year-old Mellor took the step after he learned that the Real Madrid star had been bombarding the retired glamour model with "late-night texts", asking her to ring him up on Facebook Messenger.

The Portuguese striker has reportedly been friends with Sugden since meeting her at London nightclubs when he was playing for Manchester United in England.

Despite moving to Spain to join Real Madrid in 2009, the 32-year-old footballer allegedly still keeps pestering Sugden with "weird" messages on social media, often asking her when she will have children.

"They're friendly enough, but sometimes turn a bit weird," a source told the publication. "She's mentioned several times that she has a fiancé, but he doesn't seem to take notice.

"In the end, Oliver found out and sent Ronaldo a polite message asking him to back off. Since then, Ronaldo has deleted the conversations," the source added. "Rhian's not heard a peep since. She's pleased. She has no interest in him."

The Sun has also shared a screenshot of an alleged text conversation between Ronaldo and Sugden.

"I will call you in one hour if you send a number, be private number," Ronaldo allegedly said in the message. "I'm at hotel."

Sugden replied, "I can't talk tonight. I'm sorry. I'm just about to pick my fellow up from work and then we are going for drinks. I don't think he would approve of me talking to you at 11pm."

Ronaldo, who is a relationship with Georgina Rodriguez, was spotted with his partner on her 24th birthday at a Marbella beach club on Sunday, 28 January. Ronaldo had his arms around Rodriguez as the couple seemed to be really into each other.

In November last year, the couple welcomed their first child together. They have named the baby girl Alana. Ronaldo is also a father to Cristiano Jnr, 7, and eight-month-old twins Eva and Mateo, who were conceived via surrogacy.