Paul McCartney at the center of a paternity row

Former Beatles star Sir Paul McCartney is at the center of a paternity investigation, over claims that he faked a DNA test more than 20 years ago.

Bettina Hubers, 46, claims that the Beatles legend is her biological father, as he apparently had an affair with her mother, Erica, while he and the band were playing in Hamburg in the early 1960s.

McCartney has since denied the paternity, claiming to have taken a DNA test proving that he's not the her father back in 1983.

But Hubers is now accusing McCartney of "faking" the test by sending a body double to give a blood sample.

She says, "The signature on the documents he signed at the time was false. We found that the signature is from a right-handed person and he is not. "I want a new paternity test. It is my right. It has taken so long because we have been fighting to find out the truth." A spokesman for the public prosecutor's office in Berlin confirmed they are investigating a paternity case involving McCartney.

If prosecutors find there is a case to answer, the singer could be arrested for fraud the next time he visits Germany.