Addison Forbes Montgomery is set to make an appearance in multiple episodes in the forthcoming season of the medical drama.

With such a huge cast in its arsenal after a 17 season run, it's no surprise to hear that another former cast member of the popular series will be making their return. Kate Walsh is set to reprise her 'Grey's Anatomy' role, a role that she hasn't played since exiting the drama after season three.

She did, however, go on to star in her own spin-off series 'Private Practice'. The series saw her character of Addison Montgomery leave Seattle and head to Los Angeles, and it ran for six seasons until 2013.

However, even though Walsh previously stated that her time on the medical drama had "wrapped up" to TVLine in the past, she seemed open to returning at some point in the future. The actor will star in season 18, which is set to premier in the States on September 30.

Kate Walsh took over the 'Grey's Anatomy' Instagram page to confirm the announcement, saying: "I’m so excited to be home again, joining Shonda [Rhimes, series creator], Ellen [Pompeo, series regular] and the rest of the cast."

Series 17 of the medical drama saw a number of former series regulars pop up for brief moments, including Patrick Dempsey and T. R. Knight.

Since leaving 'Grey's Anatomy' and 'Private Practice', Kate Walsh has played a number of fun roles on our screens. She played Olivia Baker on '13 Reasons Why', Madeline Wheeler in 'Emily in Paris', and The Handler on Netflix's superhero series 'The Umbrella Academy'.

'Grey's Anatomy' seasons one to 16 are available to stream on Amazon Prime; season 17 is available to watch via Sky Witness and NOW.