Well this is unexpected. 

At the beginning of the year, Ridley Scott was pretty adamant that the star of Prometheus, Noomi Rapace would not be returning for the follow up, Alien: Covenant. However Deadline, are now reporting that Rapace is currently on set in Australia filming scenes for the latest installment of the Alien franchise. 

Considering Rapace's character Elizabeth Shaw was the only human character left alive at the end of Prometheus, it was expected she would return for the sequel but then Katherine Waterson was cast in the lead role and it was assumed that the story's timeline may have moved beyond Shaw's lifespan. According to Deadline's report, Rapace is only filming a week's worth of scenes which means her involvement in the story is unlikely to amount to much more than just a bit part or cameo.

Alien: Covenant will be released in August next year.