UPDATE - 12/10@2:57PM: Here's a review of the show from NEXT magazine:
... Like the perfect holiday host, Kim comes in hot, opening the show singing one of his mega-hits, Sugar Sugar, before swinging into another chart-topper, Baby I Love You. Kim brings out everybody’s favourite “uncle” and holiday guest at the top of the show, Rush guitarist Alex Lifeson, a regular at Kim’s charity gigs and a clear fan favourite, drawing hoots and applause all night as he sits in with many of the evening’s acts. ...
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UPDATE - 12/5@7:39PM: Here are a couple more videos with Alex performing with Broken Social Scene:
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UPDATE - 12/5@10:37AM: Here's Sugar Sugar!
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UPDATE - 12/5@10:32AM: Here's Alex and others with Andy Kim performing the classic Rock My Gently:
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UPDATE - 12/5@10:10AM: Here's Alex performing a Christmas medley with the Barenaked Ladies:
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UPDATE - 12/4@10:12PM: 
Reader Ian G is attending the show and sent along a couple photos, including this one showing Lerxst looking very serious, along with this one of Alex and another artist (unsure offhand who it is).
The 20th annual Andy Kim Christmas show in support of CAMH Gifts Of Light takes place TONIGHT at Massey Hall in Toronto, and Rush's Alex Lifeson will be one of the many artists to participate. Other guest performers will include Broken Social Scene, Billy Talent, Barenaked Ladies, William Prince, Dan Hill, Molly Johnson, and more. From the announcement:
Andy Kim's annual Christmas show is returning to Toronto's Massey Hall, and the veteran musician has announced the guests who will be joining him for the show on December 4.
For the 20th annual Andy Kim Christmas, the bill includes Broken Social Scene, Alex Lifeson, Billy Talent, Barenaked Ladies, William Prince, Dan Hill, Molly Johnson and more guests to be announced in the coming weeks.
"There is something fascinating about a 20th anniversary celebration. With all the excitement of putting this year's 20th AK Christmas, I'm reminded of the first one," Kim said in a statement. "Filled with the honest belief that our musical community will help me ease into the Christmas holiday spirit."
All proceeds from the event will be donated to CAMH's Gifts of Light. Tickets go on sale this Friday at 10 a.m. local time.
You can get more information and purchase tickets at this location. Alex has participated in the Andy Kim Christmas Show several times in the past, most recently last year where he performed the Andy Kim classic Sugar Sugar with Kim, and also sat in on the all-star jam of the FREE classic All Right Now. You can get full coverage from last year's event here.
