Campaigners have raised more than half of the £2.7m target to save a masterpiece that has hung at a Wakefield stately home for more than 200 years.
In September, The National Trust and the Art Fund launched a bid to keep The Procession to Calvary by Pieter Brueghel the Younger, at Nostell Priory near Wakefield.
The old master, which is still owned by Lord St Oswald, and depicts Christ carrying his cross on his way to crucifixion has been put up for sale and it is feared it could be taken away from public view.
Donations, which include 460,000 from the public, are now approaching 1.4m but more are needed to meet the 2.7m target by Christmas.
To encourage further donations, The Procession to Calvary will be included in The Big Give Christmas Challenge 2010, which aims to raise money for hundreds of charities.
From December 6-10, the five day challenge will enable donors to double their donations for free if made via The Big Give website www.thebiggive.org.uk/donate/nostell.
Fiona Reynolds, Director-General of the National Trust, said: "We are delighted that the fundraising appeal to save this wonderful painting is approaching 1.4m and our thanks go to everyone who has supported it so far.
"But we have some way to go and we hope many more people can help us to reach our target to keep The Procession to Calvary at Nostell Priory where it belongs."
The painting will be on display at the York Art Gallery until Christmas.
Stephen Deuchar, Director of the Art Fund, said: "We urge as many as possible to double their donations through The Big Give and help us secure the painting for Nostell in time for Christmas."