An insider confirmed to DS that the two singer-songwriters will appear at the event, which is also said to feature a giant man-made ski slope and a light show similar to what was seen during the last Olympics in Beijing.
McLachlan's music is already connected to the Olympic broadcast as network NBC chose her original song 'One Dream' to promote its coverage of the competition. It is likely that she will choose to perform this track during her ceremonial appearance as well.
Meanwhile, Lang is currently promoting a new best-of album called Recollection.
Other acts seen at last night's dress rehearsal were Nelly Furtado, Bryan Adams and Nikki Yanofsky. It is being speculated that the 16-year-old jazz star will sing 'I Believe', the official song for the Canadian broadcast.