Michael Douglas and Catherine Zeta-Jones

Michael Douglas and Catherine Zeta-Jones

Michael Douglas and Catherine Zeta-Jones worked hard to get their marriage back on track.

The couple, who announced they were taking a temporary "break" from their 13-year marriage in August, posed on the red carpet for the first time since they reportedly reunited in November at the opening night of 'The Library' at The Public Theatre in New York City on Tuesday night (15.04.14).

And a long-time friend of the duo - who have son, Dylan, 13, and daughter, Carys, 11 - revealed they never gave up hope and steadily worked on their rebuilding their relationship.

The source told PEOPLE.com: "It is so easy to just give up. But they wanted to put in the work. I'm really happy for them."

The Welsh actress, 44, and the 69-year-old actor looked happy and relaxed as they attended the event together.

Michael's mother, Diana Douglas, first confirmed that he and Catherine were back together last month.

She said: "They are together. I knew they would work it out. They're both gentle people, not hysterical. They're always very affectionate and easy with each other. I figured the more everybody stayed out of it the better."

The couple had a difficult few years during which 'Red 2' star Catherine admitted that she suffers from bipolar disorder - which has led to her spending time in rehab for depression - and Michael battled with tongue cancer.