Patrick Murray has blamed his former 20-a-day smoking habit after he was diagnosed with lung disease.
The 61-year-old actor - who played Mickey Pearce in legendary sitcom 'Only Fools and Horses' - quit cigarettes four years ago, but believes the damage was already done to his body as a result of years of puffing away.
He told the Daily Star newspaper: "I used to be a 20-a-day smoker, but gave it up as soon as my daughter was born four years ago.
"I guess it had already done damage to my lungs. In my day, there were even commercials saying smoking was good for you and people smoked on TV and films."
Patrick has been receiving treatment for lung condition obstructive pulmonary disease (COPD), and it was thought the medical condition had forced him to pull out of a bus trip which would've paid tribute to the show's classic 'Jolly Boys' Outing' episode.
However, he claims he was still keen to go on the jaunt.
He said: "It is true that I have COPD, but I was still up for the trip in August."
His agent Mark Neale recently said: "Pat was really disappointed to let so many people down, but he is having treatment and hopes to arrange it again later in the year."
Talks were said to have taken place to try to re-arrange the trip for October, but Patrick says he will not take part then because it is "supposed to be a summer outing".
The trip would've seen Patrick travel on an open-top double decker bus with 70 fans from Leysdown-on-Sea in Kent to Margate to raise money for the children's hospice Demelza.
The jaunt is a nod to the 'Only Fools' special episode 'Jolly Boys' Outing', which aired on Christmas Day in 1989 with more than 20 million people tuning in to see the bus explode before Mickey, Del Boy Trotter (Sir David Jason), Rodney Trotter (Nicholas Lyndhurst) and their Peckham pals reached Margate.