The stars previously shared a stage in a La Jolla Playhouse production.
Joe Manganiello is speaking out about Doris Roberts.
As the 39-year-old actor continues to keep mum regarding reports that he recently underwent surgery for "extremely serious" appendicitis, he has taken to Twitter to pay tribute to the late Emmy winner.
"I'll miss you Doris," Manganiello wrote on Tuesday. "Thank you for all of the laughs and the stories. #RIPDorisRoberts You are a legend."
WATCH: Doris Roberts Dead at 90
The screen stars previously shared a stage in a 2009 La Jolla Playhouse production of Unusual Acts of Devotion, with Manganiello playing a jazz musician and Roberts, a neighbor for whom his macho character has a soft spot.
As ET previously reported, Manganiello pulled out of a charity event on Sunday due to a "health issue," while TMZ alleged that the Magic Mike star underwent surgery to remove his appendix late last week. Manganiello's rep had no comment when ET reached out about the appendicitis report.
Last week, the actor also had to bow out of History Channel's Navy SEAL drama series, Six, reportedly for health reasons and the physical demands of the show.
Manganiello is the latest of Roberts' many former co-stars to pay tribute to her memory. The actress best known for playing Marie Barone on Everybody Loves Raymond died Sunday of natural causes. She was 90.
WATCH: Ray Romano Remembers Doris Roberts and Her 'Grand Love for Life' in Touching Tribute