Rachel Bilson and Chris Carmack had a mini "The O.C." reunion this week.
"'Welcome to Nashville [expletive] ......this is how it's done in Tennessee' @realcarmack #propergreeting #nashvillecmt," Bilson captioned a photo of herself and Carmack on set.
Carmack, who portrays Will Lexington, first appeared in Season 1, and was made a series regular in Season 2.
Bilson and former "Empire" star Kaitlin Doubleday joined the "Nashville" cast last week in the wake of Connie Britton's departure.
"We welcome Rachel and Kaitlin into our incredibly talented ensemble," executive producer Marshall Herskovitz said.
"We fondly anticipate the second half of the season filled with surprising twists and turns that make Nashville so beloved by the fans."
Carmack played Luke in Seasons 1 and 2 of "The O.C.," while Bilson starred as Summer throughout the show's four-season run from 2003 to 2007.
The actress had expressed interest in an official reunion in 2013.
"If everyone wanted to do it, I'm sure it would be fun," she told Us Weekly.
"Nashville" is presently on mid-season break.