McIlroy is currently in the United Arab Emirates to begin his European Tour campaign at the Abu Dhabi HSBC Golf Championship.
The Northern Irishman always likes to get up and running during the desert swing and will face Spieth this week as well.
The two men, along with Australia's Jason Day, look set to dominate the golfing world over the next few years, and they will tee it up in the California event, which gets under way on February 18 at Riviera Country Club.
It will be the four-time major winner's debut in the event and his first appearance on this season's PGA Tour before both he and the Tour head to Florida for the Honda Classic.
And Northern Trust Open organisers were understandably delighted that the duo are on board.
"We're thrilled to welcome Rory McIlroy to the Northern Trust Open field for the first time, as well as world No 1 Jordan Spieth," said chairman and chief executive officer Frederick H Waddell.
"There are so many strong, young players with compelling storylines ready to tee it up at Riviera this year; it's going to be a fantastic event." - Female First
Original source: McIlroy, Spieth set for Northern Trust duel