Eilish McColgan aims to become the first Scottish track and field athlete to compete at four Olympics.
The 29-year-old middle-distance runner will make her third appearance in the 5,000m at next summer's rearranged Tokyo Games.
And she will then switch focus to the marathon as she bids to make Paris 2024.
"It's a scary prospect but it's always been something I've wanted to do," said McColgan of the step up to marathon.
"I probably would have gone to it a little bit sooner had the Olympics not been delayed. For the following Olympic Games I'd hope to challenge for a spot on the marathon team."
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McColgan competed in the steeplechase at London 2012, then reached the 5,000m final in Rio four years later.
A European silver medallist over the latter distance, she broke her mother Liz's Scottish 10-mile record to retain her title at the Great South Run in October last year.
And she could look to use the marathon at the 2022 Commonwealth Games in Birmingham as a stepping stone for Paris two years later.
"After doing the Great South Run I've got comfortable over the 10-mile distance and it's given me confidence to look forward to my first half marathon," she added.