Is Princess Charlene of Monaco pregnant with twins?

Rumours have begun to circulate that Princess Charlene of Monaco is pregnant with twins.

Derek Watts, a close friend of Charlene's father Mike Whittstock, appeared to unintentionally break the exciting news when he tweeted that Mike had called him to tell him the princess is expecting not one, but two new arrivals.

"My old Bulawayo schoolmate Mike Wittstock has phoned to say his daughter is pregnant with twins," wrote the South African TV presenter. "Congrats Princess Charlene and Albert!"

Princess Charlene of Monaco

Shortly after posting the message, however, Derek deleted it, suggesting that he had been told that the news was to stay under wraps for a little while longer.

Despite Derek removing the tweet, news outlets in Charlene's native country have begun claiming that she is pregnant with twins.

The Benoni City Times reported that Mike told them he was excited to be expecting two more grandchildren.

"I am very happy about the news and now my wife and I are going to have four grandchildren," he told the newspaper, making reference to his sons Gareth and Sean's children. "My phone has been ringing non-stop today, but Charlene informed me about her pregnancy on the weekend of 24 May."

Princess Charlene and Prince Albert

Royal watchers have noted that the official statement from the House of Grimaldi confirming Charlene's pregnancy did not specify if one or more children would be due.

"T.S.H the Prince and the Princess of Monaco are delighted to announce the pregnancy of H.S.H. Princess Charlene," read the announcement. "The birth is expected at the end of the year."

While this is Charlene's first pregnancy, Prince Albert is already father to two children, 22-year-old daughter Jazmin Grace Grimaldi, and ten-year-old son Alexandre Coste.