Accompanied by the Duke of Edinburgh, the Queen will not only open train company Eurostar's new £800M terminal at St Pancras station but also open the High Speed 1 rail link, formerly known as the Channel Tunnel Rail Link.
Next week, Eurostar switches its terminal from Waterloo station to St Pancras and will be able to cut London to Paris journey times by 20 minutes to about two hours 15 minutes.
The ceremony will involve three trains arriving at St Pancras. Their three drivers will meet the Queen, who will also be introduced to those who have transformed the late-Victorian building of St Pancras into a 21st century terminal.
The French had their high-speed Channel Tunnel link ready in 1993 - a year before the tunnel was officially opened - while the Belgians completed their link in the late-1990s.
Section 1 of the UK fast link - from Folkestone to Ebbsfleet in north Kent - was finally completed in autumn 2003. Section 2, from Ebbsfleet to St Pancras, has now been finished.
Work began on transforming St Pancras in 2001 to enable it to accommodate domestic rail services and Eurostar trains to and from France and Belgium.
More than 150 years of dirt has been removed from the brick work and a new roof has been fitted with 18,000 panes of self-cleaning glass.
The front of the station will open as a five-star hotel in 2009.
St Pancras will eventually be five stations in one - housing Eurostar, high-speed domestic services to Kent from 2009, Midland Mainline, Thameslink and six Tube lines.