DoorDash has announced that it’s buying Instacart in a deal valued at approximately $17 billion. The acquisition will give DoorDash a bigger presence in online grocery delivery via Instacart’s established grocery marketplace and retailer partnerships.

DoorDash, which started as a restaurant courier service, already has its own grocery delivery business, but that faces ongoing competition from Instacart, Uber, Walmart, and Amazon. DoorDash is also incentivized to diversify further because its rivals have been stepping into the food delivery territory it’s best known for, with Uber acquiring Postmates and Delivery Hero.

Rumors around the deal started circulating last week after The Information reported that Instacart was in talks with rival platforms Uber and DoorDash regarding a potential sale. By Monday, The Wall Street Journal reported that DoorDash was in “advanced talks” with Instacart, and that a deal could be finalized “as soon as this week.”