Michael Weatherly's final "NCIS" episode is fast approaching and growing speculation is an international manhunt for a killer of federal agents could be what comes to separate him from his longtime crew members. After 13 seasons, Weatherly's Agent Tony DiNozzo character's final episode is slated to air as part of the show's "Family First" entitled May 17, 2016 season finale.

TV's most watched drama series newest cast members, "24" alum Sarah Clarke and British actor Duane Henry, are also both set to appear on the show's final episode. Weatherly first announced early this year that he planned to leave the show at the end of the season to pursue other options.

Weatherly's Final Show to Cover Much Ground

"We're really trying to give everybody something that leaves them satisfied," series show-runner Gary Glasberg recently told reporters. He added the task of ending the storyline of one of the show's few remaining original cast members has required "lots of planning."

Michelle Obama set to Guest Star in Upcoming Episode

Meanwhile, word is First Lady Michelle Obama is also slated to guest appear in an upcoming episode.

Mark Harmon, who stars as Agent Leroy Jethro Gibbs, was recently spotted filming scenes outside the White House and revealed the first lady was soon scheduled to begin shooting scenes.   

A spokesperson from the CBS aired show later confirmed that filming is now taking place in Washington, but declined to talk about any plans involving Obama.

What role she might take on also remains a mystery, as does any details about when any such episode might air. The guest starring appearance wouldn't be a first for Obama, who previously appeared in a Season 6 episode of "Parks and Recreation" to promote her "Moving Up" campaign.

"NCIS" returns to the airwaves on April 19, with the airing of a "Return to Sender" themed episode.