Katherine Jenkins has called the police after receiving death threats on Twitter.
However, an unnamed social networker, who is believed to be a 17-year-old boy, has threatened to stab Jenkins if David and his wife Victoria break up.
He tweeted: "Honestly, and you all said my dislike of Katherine Jenkins was irrational (it is, and that b**** is getting cut if David and Posh split.
"Emotional support will be needed if any truth comes from this. I love Posh and Becks."
A spokesman for Jenkins told The Sun: "Due to the serious nature of the threats, the tweets have been reported to the police."
David and Victoria, who have four children together, have been married since July 4, 1999.