On the heels of unveiling the Tesla all-electric semi-truck and a second-generation Roadster in November, Elon Musk took to Twitter today to ask his fans how Tesla can further improve.

In response to someone who requested a Tesla pickup truck, Musk said, “I promise that we will make a pickup truck right after Model Y. Have had the core design/engineering elements in my mind for almost 5 years. Am dying to build it.”

In terms of size, Musk said it would be comparable to Ford’s F-150 total size, but “maybe slightly bigger to account for a really gamechanging (I think) feature I’d like to add.”

This isn’t too surprising, given that Musk said earlier this year Tesla planned to show off an electric pickup sometime within the next couple of years. Then, at Tesla’s big semi-truck unveiling in November, Musk revealed an image of an electric pickup truck, which was based on the architecture of the semi-truck. And in Musk’s “Master Plan, Part Deux” in 2016, he described Tesla’s plans to create “a new kind of pickup truck.”

The only hint we have around timing is that Tesla would start making the pickup truck right after Model Y, which Tesla has yet to unveil. The Model Y is a crossover/small SUV vehicle that is reportedly in the more advanced stages of development. Tesla expects to launch the Model Y by 2020.