Fifty thousand petals - one for every person cared for in the past 40-years at St Gemma's Hospice - will be released from the ceiling during an emotional Night To Remember at Leeds Town Hall.
Leeds Symphony Orchestra will entertain with popular classical music.
A new hospice choir, consisting of staff and volunteers. will give a debut performance of songs including Ain’t No Mountain High Enough and Land of Hope and Glory.
The evening will also include a dance performance, readings, short films about the hospice and a chance to hear from those who have first-hand experience of St Gemma’s care.
It will be hosted by ITV’s Duncan Wood and Christine Talbot, on Wednesday, March 21.
Today St Gemma's bosses said the ruby anniversary commemorations will give them a chance to thank the public who have helped to care for 50,000 people by keeping the hospice going since it opened in 1978.
They urged people to buy tickets in advance for just £5 each by calling 0113 218 5550 or visiting events.st-gemma.co.uk.
"It is a chance to remember our loved ones and all those who have been in St Gemma’s care since it opened," said spokesperson.
"Towards the end of the evening there will be a moments’ silence followed by a spectacular cascade of 50,000 petals which will fall from the top of the Hall, each representing one of the 50,000 people who have been cared for at the hospice or at home.
"Forty years ago the people of Leeds filled the Town Hall to hear about the plans for a new hospice and offer funds to support it. Now all these years later it is fitting that the community and St Gemma’s are returning there again for this superb event.
"None of those patients would have been cared for without public support and it cannot continue without it either, so St Gemma’s hopes to see everyone there with friends and family to commemorate this special year."