Jennings is to appear on the show Nov. 3-7.
The new "Ask the Expert" lifeline enables contestants to connect with a pre-determined "expert" via a live face-to-face Skype video call on any question past the $1,000 level.
Starring Meredith Vieira as host, "Millionaire" premiered its seventh season last month.
"When the idea of 'Ask the Expert' was introduced, the first name we discussed was Ken Jennings," "Millionaire" executive producer Michael Davies said in a statement.
In 2004, Jennings made television history when he was crowned the winner of 74 consecutive episodes of "Jeopardy," winning more than $2.5 million. Jennings holds the record for the longest winning streak in game-show history.
"Winning big on a quiz show was the most fun I've ever had, so hopefully I can make that same dream come true for a few other people, as well," said Jennings.
Other "experts" who have appeared on "Millionaire" this season include Bill Nye the Science Guy, actor Jay Thomas, Headline News's Robin Meade and former "Millionaire" contestants Ogi Ogas and Nancy Christy.