"These droids can be so damn intractable. But we'll go until we get it right! #UntitledHanSoloMovie," Howard captioned the on-set image on Twitter.
The new droid resembles franchise regular R2-D2 but with a different silver, white and gold look.
The image is the latest tease the director has shared on Twitter after he took over directing duties on the film in place of filmmakers Phil Lord and Christopher Miller who were booted off the project over "different creative visions."
In a recent interview with The Hollywood Reporter, Howard assured fans that the film is "coming along great" despite the change in directors.
"It's a fantastic script, a great cast and I am having a fantastic creative experience with it," he said. "It's a great young cast, incredibly strong - smart, funny people who love their characters and love being part of this. I think we'll be able to do something that is a lot of fun."
The still film is set to open in theaters on May 25, 2018.