LOS ANGELES • You would think that Beyonce's fans would be very happy that a trusted source - the singer's father himself - has confirmed that she has given birth to twins.

But Mr Mathew Knowles' comments have not gone down well with some among the Beyhive (the term for the superstar's fans) and they are abuzz with anger.

"They're here! #beyonce #twins #jayz #happybirthday," Beyonce's dad wrote on Twitter and Instagram on Sunday.

He also enclosed an image of a digital card that reads "Happy Birthday to the twins! Love, Granddad" .

Many media reports had said that the 35-year-old singer, who is married to rap mogul Jay Z, 47, had given birth last Saturday.

The power couple also have a daughter, Blue Ivy, five.

After Mr Knowles posted his messages online, some fans went on the attack.

"It's not real until the queen herself reveals it," one fan tweeted.

Another snapped: "Just had to ruin it for Bey did you."

Yet another fan fumed: "You should delete this and let Bey announce it."

Neither Beyonce nor Jay Z has made any announcement about the birth, Reuters reported.

Social media was abuzz in February, when she posted a photo of herself wearing a long veil and lingerie and caressing a noticeable baby bump.

The media and fans were also agog over her expensive maternity wardrobe and search for a bigger family home in the run-up to the twins' birth.