David Coulthard attends his sister Lynsay's wedding in 2011 .

Retired Formula One racing driver David Coulthard is in mourning after his younger sister died of a suspected heart attack just two years after the star's other sister also died in her sleep.

Lynsay Jackson, 35, mother of ten-month-old Emilie Anne, is believed to have died of heart failure at around 4am this morning.

The trainee nurse is understood to have gone to bed complaining of stomach pains.

Her family were too upset to comment. Her parents Joyce, 65 and Duncan, 66, from Twynholm in Dumfries and Galloway, are understood to be flying back from Australia after hearing the news.

The former racing star is thought to have been informed of his sister's death moments before appearing on BBC One's Saturday Kitchen Live yesterday. His agent James Williamson said: "He found out just before he went on air."

Police attended Mrs Jackson's home in Crossmichael, Castle Douglas, in the early hours of the morning on Saturday 9 February, but said they were not treating Lynsay's death as suspicious.

Hairdresser Charlene Saunderson, a neighbour in Crossmichael where the Jackson family moved last year, said: "I heard all the commotion. There were six police cars and lots of family cars.

"I knew there was something wrong because the ambulance left with no one in it, then her brother took the baby away. Then the doctor and a forensic team came."

"We met Lynsay and Will out recently. I think the family were really good to her. The night we met them about two weeks ago, they had stopped off at a local pub for a drink.

"Lynsay liked having a laugh. She was witty, and if she had something to say she would say it. I feel really awful as she said that night at the pub 'just come over for a tea or a coffee' and I never did. I feel so awful.

"She was into bodyfit bootcamp and was doing well with. We tried to go running and she wanted to get involved in the community. People are just shocked, especially as she was so young.'

Mrs Jackson married her husband Will, an environmental health officer, in 2011.

David was known to be particularly close to his sister, and dedicated his 10<sup>th Grand Prix in Brazil in 2001 to Lynsay, saying: "It was my sister's birthday and she asked me for a win so I dedicate this race to her."

Lynsay was reduced to tears, saying at the time: "I phoned David last Tuesday to wish him a happy 30th birthday and he said he had not managed to get me a present. I was a bit miffed so when he won in Brazil and announced it was dedicated to me it was the best birthday present ever.

"We watched the race on a German channel and they have breaks which seem to last half an hour so we kept having to phone home to Twynholm. When David finished the final lap we were ecstatic."

Nine years ago, the family were united at the funeral of their grandmother, Margaret Coulthard, 88, who died in a care home in 2004. David's other sister Elaine Rowan, who was given up for adoption as a baby, died in her sleep in September 2011.