The Scottish Liberal Democrat leader will run more than 100 miles in three days to raise money for a mental health charity.
Willie Rennie is running the 117-mile length of the Fife coastal path over the Easter weekend - equivalent to more than four marathons.
The North East Fife MSP has already raised more than £4,000 for the Scottish Association for Mental Health (SAMH).
Speaking ahead of the run, he said: "Over the Easter weekend I'll be running the 117-mile route from Kincardine to Newburgh, the full length of the Fife coastal path.
"I'm doing it to raise money for the great mental health charity SAMH. I've seen the fantastic work they do for so many people across the country but they need more money to help more people.
"Across Scotland hundreds of vulnerable people are struggling to cope with issues including eating disorders, anxiety, depression and bullying. SAMH do absolutely vital work in supporting them."
Donations can be made at www.justgiving.com/fundraising/Willie-Rennie