From an interview with the actress Jennifer Aniston in the September issue of Elle:
On being labeled a “lonely girl”:"I'm not going to ignore the pink elephant in the living room. It's fine. I can take it. If I'm the emblem for 'this is what it looks like to be the lonely girl getting on with her life,' so be it."
Ms. Aniston colorized the idiom, which is usually stated as "the [color-unspecified] elephant in the room." Its meaning: "an important and obvious topic, which everyone present is aware of, but which isn't discussed, as such discussion is considered to be uncomfortable." (Source: The Phrase Finder.) The room is usually unspecified, too—when used in a business context, the room may be a conference room. The "living room" association was first made in the title of a 1984 book, An Elephant in the Living Room: A Leader's Guide for Helping Children of Alcoholics.
Speaking of alcoholics, "seeing pink elephants" is a euphemism, reportedly coined by none other than Jack London*, for "hallucinating while in a drunken stupor." When the title character in Disney's Dumbo accidentally drinks a bucket of booze, he dreams about "pink elephants on parade."
In the absence of any inside info about her experience with liquid intoxicants, I will venture to guess that Aniston simply conflated the two idioms.
For more celebrity malapropisms, see Celebrity Usage and Celebrity Grammar. Yes, I know that the most recent posts are dated June 2006 and that all three sites are supposed to redirect to Celebrity English, but Celebrity English n'existe pas. And the archives, with their combination of inane celebrity blather and deadpan academic critique, are still fun to read.
* That post, written by a "Cocktail Shaker & Barware collector, amature [sic] mixologist, cocktail enthusist [sic], and all around lover of good food and drink" in the blog Shaken & Stirred, is a trove of pink elephantiana.