Usain Bolt looks likely to race at the London Anniversary Games at the Olympic Stadium in July.
His agent confirmed "positive negotiations" had been held with the organisers with a view to the world's fastest man competing at the Diamond League meeting on 26 and 27 July.
Bolt's agent Ricky Simms said in a brief statement: "We are having positive negotiations, but have still some things to finalise."
The meeting is expected to attract a host of star names as it marks the anniversary of the London 2012 opening ceremony.
It would be the first time Bolt has competed in Britain since 2009, except the Olympics.
The double Olympic 100, 200 and 4x100 metres champion has stayed away because under UK law he would have had to pay tax on his lucrative endorsement earnings, meaning it would have cost him money to compete, regardless of his appearance fee.
But Chancellor George Osborne has announced a one-off exemption for overseas athletes taking part in the Anniversary Games.
The Daily Telegraph reported Bolt had agreed to compete on both days of the meeting, likely one individual sprint race plus the 4x100m relay.
It claimed the 26-year-old would receive an estimated £500,000 for his two-day appearance.
UK Athletics would not confirm whether an agreement had been signed with the Jamaican.
A spokesman told Press Association Sport: "We are working hard to put together the best possible field."
The London Anniversary Games takes place two weeks before the World Championships in Moscow, where Bolt will bid to regain the 100m crown he lost in 2011 for false-starting in the final and retain his 200m title.
The meeting, which was moved from Crystal Palace to the Olympic Stadium, is set to be one of the sporting highlights of the summer, with British Olympic champions like Jessica Ennis and Mo Farah also expected to compete.
It will also feature a day of Paralympic action on 28 July.
Bolt has already confirmed he will race over 100m in Rome on 6 June, over 200m in Oslo on 23 June, in the sprint relay in Ostrava on June 27, over 200m in Paris on 6 July and over an unconfirmed distance in Brussels on 6 September.
He is due to race over 150m on a track on Copacabana beach on Sunday where he will bid to beat his world best time of 14.35 seconds, set on the streets of Manchester in 2009.