Kelly has already completed the race twice despite arthritic knees and is preparing to go through the pain barrier again on Sunday, April 28.
She is Ward Manager here which has provided her with the motivation to take part and she is hoping to raise £20,000 for St Ann’s along with other members of the team.
The Romiley mum lost eight stone after realising that as a nurse she needed to show her patients the benefits of a healthier lifestyle.
However, her long-distance running days are numbered because she has Ehlers Danlos Syndrome, a genetic condition affecting her joints.
Kelly wore her nurse’s uniform in last year’s event, run in the hottest temperatures on record and raising £8,500 in the process.
Husband Marc Foster, a neighbourhood police sergeant, is part of the St Ann’s team along with Amanda Connors, Day Therapy Sister at the Heald Green site.
This has got to be my last marathon and I'm not certain to finish but I want to run for our patients. It costs £20,000 a day to run St Ann's Hospice so that's our ambitious target. Kelly Foster, Ward Manager
I haven't got a competitive bone in my body and this will be my first and last marathon. It's always been on my bucket list to do the London Marathon and it'll be good to all run together for the hospice. Amanda Connors, Day Therapy Sister
Fellow team member Mark Hayes, from Great Moor, will be tackling his first marathon after taking up running four years ago. Mark works for Vodafone who are supporting his fundraising efforts with their match funding scheme.
* To sponsor Kelly go to https://www.justgiving.com/fundraising/kelly-foster21 and for the other fundraising pages go to https://www.justgiving.com/companyteams/TeamStAnns
Any runners who want to raise funds for St Ann’s, email firstname.lastname@example.org or call the team on 0161 498 3631.