Julie Chen Moonves returns to host Big Brother Season 27, which premieres with a 90-minute episode on Thursday, July 10 at 8 p.m. ET on CBS. A second 90-minute episode will follow on Sunday, July 13 at 8 p.m. ET. RELATED: ‘Survivor 50’ Cast Photos: All The Castaways Confirmed For CBS Competition

A new “Big Brother” theme will roll out when Season 27 airs with a 90-minute premiere on July 10, starting at 8 p.m. ET/PT, followed by another 90-minute Sunday episode on July 13. While CBS previously announced the new segment “Big Brother: Unlocked,

"Big Brother" is promising a summer of mystery when Season 27 premieres next week, as seen by CBS's new first-look images of the updated house theme — aka, Hotel Mystère. "Houseguests will enter the enigmatic Hotel Mystère,