The 57-year-old travelled by train from Brussels at 5:38am for the Luxembourg leg, which he finished in just over seven hours.
He faced wind and rain but Izzard found a rainbow at one point and also stopped to enjoy the breathtaking scenery, filming the Pétrusse valley and sharing it on his Facebook page.
In one video shot five kilometres before the finish, he said “I’m not having a great time of it […] I would like this to finish. I’d like the next five kilometres to just go a bit […] just keep going.”
In 2016, the comedian ran the equivalent of 27 marathons in 27 days for Sport Relief, a feat he said was the hardest thing he had ever done. He announced his latest challenge on Twitter as an appeal for unity before the UK officially left the EU.
“In our country, and in our world, there is far too much talk about division. Let’s change that; let’s talk about unity and humanity, for unity is part of humanity,” he said.