A Tesco manager says she has discovered she is the long-lost half-sister of former Sex Pistols frontman John Lydon.
Janet Small says she would have had 'great debates' with Lydon
Janet Small, 51, of Chepstow, south Wales, says she traced her link to the singer, and star of TV show I'm a Celebrity, after adoption law changes.
Mrs Small, who admits she hated punk rock, claims they share their mother, Eileen, who gave her up for adoption before marrying Lydon's father, John.
So far the 50-year-old punk icon has not commented on the claims.
Mrs Small said members of the Lydon family, including John Lydon senior and Lydon's aunt, Pauline, accepted her claim to be Ireland-born Eileen's first child.
Speaking from her home she said: "It was a shock to find he was famous. I realised straightaway it was going to make things much harder.
"I would have been his big sis'. They [Lydon and his three brothers] would have been able to come to me. I think the family would have stayed closer together."
Records unearthed during Mrs Small's three-year research point to her mother putting her up for adoption in 1954. Mrs Small believes she was born after her mother had an affair with a barman called Patrick.
The following year Eileen married Lydon's father and started a family of four sons but, Mrs Small claims, she never told her husband about her first child.
Eileen Lydon died in 1978, three years after her eldest son started on the road to fame and fortune as Johnny Rotten of the establishment-baiting Sex Pistols.
Mrs Small said John Lydon senior gave her this photo of Eileen
Mrs Small was brought up by a couple who also adopted a son.
She grew up in the east end of London and believes it was within a few miles of the Lydon family.
She married her first husband in the year that Lydon shot to fame but said: "I hated punk.
"I was sent to convent school so I suppose I was a bit of snob. I always thought [punk rockers] were so ill-mannered.
"Their music never appealed to me. I was a big Queen fan and was into Tamla Motown."
A mother-of-two and manager for store chain Tesco, she said she had known for two years that she was related to Lydon, who has lived in the United States for many years since first finding notoriety.
But she did not make the connection until after seeing him on the ITV show I'm A Celebrity... Get Me Out of Here!
It was her husband, Nigel, who first claimed there was a family resemblance between the two.
The Sex Pistols making their American debut in Atlanta in 1978
He said: "As soon as I saw him on the telly, I said 'that's your brother'. They've got the same nose."
Mrs Small said she realised some people might be suspicious of her motives, but she had only gone public because she now wanted to prove her connection through DNA tests.
She said that in addition to Lydon and his three brothers, she has found she has five brothers and sisters on her father's side, all people she wants to get to know
She said: "When you are adopted, you want to search out your missing links. It's about the whole of the family. They all have a right to know that I exist."
Mrs Small said her natural father was still alive but was "in denial". She is seeking a DNA test from him and from Lydon or one of his brothers.
The BBC News website has sought a comment from Lydon's agent in the US, but has not yet received a reply.