Mo Farah has announced he is "back on the track" and will aim to compete in the 10,000 metres at next year's Olympic Games.
Farah has won double gold at each of the last two Olympics, taking the 5,000m and 10,000m crowns in London and Rio, but switched his focus to the marathon in 2017.
Farah won the Chicago Marathon in 2018 but has decided to return to his old stomping ground, saying on his YouTube channel: "The big news is I'm back on the track in the 10,000m in Tokyo next year.
"I hope I haven't lost my speed but I'll train hard for it and see what I can do."
Farah has seemingly been managing conflicting emotions over the past year, admitting he missed the regular competitions offered by track racing but also repeating his stated ambition of winning the London Marathon.
An eighth-placed finish in Chicago in October may have proved the catalyst for his change of heart. A week earlier Joshua Cheptegei of Uganda had inherited Farah's 10,000m crown at the World Championships, and the Briton will now look to reassert himself on a field he once ruled.
Speaking to Virgin's Chris Evans, he explained: "I decided after Chicago, not straight away, but it was on my mind.
"I was watching the World Championship in Doha. I watch the 10,000 meters, and watch other races, and part of you gets excited.
"You're seeing people winning medals, for your country and stuff, and you ask yourself. It almost felt like I needed to be there."