The "Friends" star started a frenzy when she posted a video in a spa with the soccer stud on Friday.
"Too hot in the hot tub!" Cox wrote, including the Modern Family hashtag.
"Modern Family" castmembers quickly commented, but when it came to sharing snaps of their own, they all included ones with Beckham and none with Cox.
Ferguson, who had his birthday on set that day, posted a picture with Beckham and wrote, "All I wanted for my birthday was @davidbeckham in a bathrobe!"
He also thanked his husband, Justin Mikita, who he allowed in the photo too.
Stonestreet mirrored Ferguson's excitement, but because they share a mutual love for Manchester United.
"Happy to have my ole pal and former @manchesterunited teammate @davidbeckham guest star on an upcoming episode of modern family."
"Modern Family" star Julie Bowen also fangirled out over the soccer stud.
Sharing a video where she's crawling under Beckham's legs, Bowen said she was going to "meg" him for her son.
"When your son asks you to “Meg” David Beckham (and you clearly don’t know what that means). Luckily, @davidbeckham is the nicest!" she wrote.
In the video, Beckham states, "That was so not a meg!"
While the cast seemed overjoyed with Beckham's appearance, he was over the moon to be in the presence of the "Friends" star!
"I met a new FRIEND today at work," he wrote while sharing a pic with Cox holding the show scripts.
The 11th and final season of "Modern Family" aired last month.