Japanese rider Yoshinari Matsushita has died in an accident at the Isle of Man TT qualifying session.
The 43-year-old Tyco Suzuki rider, who first competed in the iconic Manx event in 2009, was only entered into the race earlier in the day.
Matsushita is the 21st rider to die at the races since 2000.
"Yoshi was a really popular competitor who had a large number of friends in the TT Races paddock," clerk of the course Gary Thompson said.
"He was a genuine and friendly character who always had time for everyone. He will be sorely missed."
The coroners have been informed and an investigation into the circumstances of the accident is under way.
Matsushita's TT entry for the Northern Ireland-based Tyco Suzuki team was only announced earlier on Monday when it was revealed that he would up teaming up with Guy Martin and Josh Brookes in the Supersport 600 event.
The Japanese rider was a regular competitor in the Superstock and Superbike classes and finished fifth in the 2011 TT Zero for electric bikes.
Earlier on Monday, Matsushita had spoken of his delight at being given the late chance to compete for the Tyco Suzuki team.
"As a member of this great team for the TT, I draw the full power to be able to use their experience to fight this monster course at best. I did not ever think a miracle like this would ever happen," Matsushita had said.
An official statement on the TT website read: "ACU Events Ltd regrets to announce that Japanese rider Yoshinari Matsushita, 43, was killed during the qualifying session at the 2013 Isle of Man TT Races in an incident at Ballacrye in the north of the island. The session was immediately red-flagged following the accident."
British MotoGP rider Cal Crutchlow tweeted: "Sad news from TT tonight. Thoughts are with Yoshinari family and all involved."
Tyco Suzuki manager Phil Neill said that everyone in the Northern Ireland-based team had been "devastated" by Matsushita's death.
"We were very much looking forward to working with Yoshinari during TT2013 and pass on our deepest condolences to his family and fellow team members," added Neill.