The 57-year-old Friends star wished her partner a happy 45th birthday on Saturday with a sweet photo of the couple snuggled up on her couch from the hit sitcom's iconic set.
"Happy Birthday to my best friend and love. He's the kindest, most patient, best listener, curious, caring, not to mention talented and gorgeous partner. I love you jmd. x," she captioned the image.
Cox and McDaid have been together since 2013. The couple got engaged in 2014 before eventually breaking it off, though they still remaining together.
McDaid was stuck in Europe for nine months after COVID-19 forced the musician to quarantine in isolation. During an appearance on the Mother's Day episode of The Ellen DeGeneres Show in 2020, Cox said it had already been the longest the couple had ever been separated.
"He supposed to go to Switzerland to write and instead had to go to England," Cox told DeGeneres. "Then all of a sudden, this all happened and they called a quarantine."
The pair celebrated their seventh anniversary in September while McDaid was stranded overseas due to the coronavirus pandemic. Cox honored the occasion with a heartfelt Instagram post.
"7 years ago today I had my first date with this incredible man... and my life was changed forever. I love you J ♥️," Cox captioned a video montage of photos from their relationship.
The Cougar Town actress told DeGeneres her only face-to-face interaction with McDaid was via video call. She even went on a Zoom date with the "Chasing Cars" singer to celebrate his previous birthday while he was in London.
"It's been 133 days since we were last together," Cox wrote alongside a screenshot of the virtual meet-up before noting, "Covid sucks."
"Happy Birthday J," she added. "I loved our lunch/dinner (LA/London time) zoom date today. I miss you madly.
The couple reunited in late 2020 and was first spotted in a video posted on December 11 for frontline workers in Derry, Ireland, where McDaid is from, ahead of the holiday season.
During an appearance on Sirius XM's The Howard Stern Show in June, Cox said it "was definitely hard" to maintain the long-distance relationship. She also grew frustrated with inconsistent COVID restrictions between countries.
"People from the U.K., they still can't come to America. You're not allowed in still, which is crazy," said the Scream actress in a call from London. "He's been vaccinated and he can't come in. I don't understand it. People can go from Florida to Los Angeles, no quarantine. I don't get it. I don't know why they can't come to America and quarantine the way I did."
When asked by Stern if they engaged in "Zoom intimacy" or phone sex, Cox said she and McDaid got creative: "Zoom intimacy? We're very intimate, but I don't know how to do that [on Zoom]. There's other kinds of intimacy."