A star of the longest-running BBC TV soap and a friend will run and cycle the length of Wales in a challenge equal to seven marathons in seven days.
The cast of Pobol y Cwm have supported Mark Flanagan
Mark Flanagan - who plays Jinx in Pobol y Cwm - and Darren Wyn Jones will travel about 160 miles (257km) from Cardiff Castle to Caernarfon Castle.
The childhood friends wanted to do something in memory of Mr Jones's father, who died of a heart attack.
Mr Jones will run the majority of the distance while Mr Flanagan will cycle.
Their challenge begins at Cardiff Castle on Sunday and they aim to reach Caernarfon Castle on Saturday 25 August.
Mr Jones, 23, who lives in Caernarfon, decided to raise money for the British Heart Foundation following the death of his father Lawrence, who suffered an aneurysm of the heart at Christmas 2005.
Mr Flanagan, 23, from Cardiff, is best known for Pobol y Cwm, which is produced by BBC Wales for the Welsh language channel S4C and has been on air since 1974.
Mr Flanagan said his friend "felt he wanted to do something positive in his father's memory" and asked him to help.
"We were in school together. I've known him since I was four.
"We used to box together as well. Darren Wyn's father was our boxing trainer."
During the challenge, sports development officer Mr Jones, a former Welsh cross-country champion, will run 4km (about 2.5 miles) followed by cycling for 1km (about 0.6 miles) while Mr Flanagan will do the opposite.
Of his training, Mr Flanagan joked: "I've been watching my alcohol intake unsuccessfully".
But he said: "it's just a matter of going to the gym every day, running 10km (6.2 miles) every day, swimming a lot and doing a lot of miles on the bike".
The first day will be the longest leg of the challenge, as they will attempt to cover 40 miles (64km).
On subsequent days, they will travel an average of 27 miles (about 43.5km) per day, which is why they have called the challenge seven marathons in seven days.
The pair, who aim to raise £2,500, will be camping each night and say getting to see so much of Wales's natural beauty will be a highlight of the trip.
Mr Flanagan said: "The one thing me and Darren Wyn are really looking forward to is indulging in the splendour of our home country."
Glenda Meakin, fundraising manager for the British Heart Foundation (BHF) in south Wales said: "The BHF is totally committed to preventing people's lives being devastated by heart disease in Wales.
"We are very grateful to Mark and Darren for their generous support of our cause and wish them all the best for such a gruelling challenge."