A lot of virtual cast reunions have taken place over the past year. After all, there's great nostalgia in seeing the actors behind your favourite shows and movies and TV shows together again. Even if it is over zoom.

The latest cast reunion saw the cast of medical drama 'ER' reconnected.

The reunion was a 2 hour long event.

Cast members George Clooney, Julianna Margulies, Noah Wyle, Anthony Edwards, Gloria Reuben, Laura Innes, Alex Kingston, Goran Visnjic, Paul McCrane, Ming-Na Wen, Laura Cerón, Yvette Freeman, and Conni Marie Brazelton were all present.

The reunion took place in honour of Earth Day. It was in aid of Waterkeeper Alliance, an organisation which aims to protect clean water globally.

Reuben serves as president for the organisation.

She said in a statement: "I am absolutely thrilled to be reuniting with my 'ER' family for a cause that is so close to my heart, and so grateful to Seth and James for allowing us to use their incredible platform to do so."

Watch the reunion here via Youtube now.

'ER' aired from 1994 to 2009. It had a total of 331 episodes spanning 15 seasons.

It's the second longest-running primetime medical drama in American television history behind 'Grey's Anatomy'.