Hospice Chaplains Penny Stephens and Annie Blampied-Radojcin led the service of readings and carols before the lights on the Christmas tree were switched on.
Light Up A Life enables the congregation to write a personal message for a relative on a star which hangs from the tree, with the names also inscribed in a book of remembrance.
Ms Stephens said: “It was the first year that Annie and I took the service, and it was a privilege to be a part of what is such a significant evening to so many people.
“It was lovely to meet people after the service and to hear their stories. The support you see between families who may have experienced a similar journey is so touching.”
The Salvation Army Band took part in the celebration, along with the Hospice Community Choir and Walthamstow Hall Junior School from Sevenoaks.