Nathan Fillion will be visited by his “Firefly” co-star Summer Glau in an upcoming episode of “Castle,” plus Conan O’Brien heads to Qatar, in today’s TV news roundup . . .

Casting News:

Fans of Joss Whedon’s “Firefly” can look forward to a small reunion on the set of “Castle.”

Summer Glau is set to guest star opposite her former “Firefly” co-star Nathan Fillion, TVLine reports. Glau will show up in episode 14, playing private detective Kendall Frost who competes against Castle in solving a mystery.

This won’t be the first time “Castle” has hosted “Firefly” reunion. Previous episodes have welcomed former Serenity crew members Gina Torres and Adam Baldwin, guest-starring with their former captain.

Premiere Dates:

Showtime is debuting the world television premiere of Spike Lee’s “Michael Jackson’s Journey from Motown to Off the Wall” on Feb. 5. The documentary, which will air multiple times throughout the month, focuses on the time of Jackson’s career as he transitioned from the lead of the Jackson 5 to a solo artist, recording his pop record “Off the Wall.”

Conan O’Brien is again taking his show overseas, this time to Qatar on Jan. 25.

“Conan in Qatar” will feature the late-night host and First Lady Michelle Obama on a trip to visit the U.S. troops station at the Al Udeid Air Base.

O’Brien has made international trips a regular part of his show. Last spring, he became the first late-night host in more than 50 years to shoot in Cuba and last November, he did a show from Armenia. He will also be returning this July to San Diego to shoot a week of shows from Comic-Con. convention.