NOTE THE CHASER ANSWERS THE QUESTION AT 3:39 BEFORE BRADLEY WALSH MENTIONS ANYTHING WHICH COULD FORM A QUESTION
ALSO NOTE COMMENTS ARE DISABLED
There is no possible way the question starting with "which Rembrandt painting was famously" Could be answered at this point. Notice the Chaser answers while the following words are revealed. An at point of initiating the vocal answer, could not have known the perceivable answer. Unless, he's been informed by other means.
Also you must take in to account the following - Why have the comments been disabled on the video. Which is currently being hosted on the youtube website.
The Chase | Full Team £20,000 Final Chase Against The Sinnerman