Lindsey prepares for walking on water zorbing challenge
23 February 2016 Last updated at 16:11 GMT
Blue Peter's Lindsey is setting off for her epic Sport Relief Challenge.
She will 'walk on water' in a giant inflatable bubble called a zorb.
She'll be running from Northern Ireland across the sea to Scotland.
It will take her hours and hours and she's had to do some serious training to get ready.
She's told Ricky how she feels just before setting off.