Michael Kelly found Kevin Spacey's departure from 'House of Cards' ''heartbreaking'' and ''strange''.

The 48-year-old actor has described the confusion that occurred when production of the political drama was suspended after his co-star - who played disgraced president Frank Underwood - was hit by a wave of allegations of sexual misconduct following Anthony Rapp's claims the 'American Beauty' star had made advances towards him when he was just 14.

After an extended hiatus, Netflix eventually announced they would go ahead with the sixth and final season of the show, but without Spacey and Michael - who plays Chief Of Staff Doug Stamper in the show - admitted it felt ''strange'' to go back without him.

He recalled to Variety: ''The crew was out of work for a long time and when everything went down, it was sort of like, 'How do we do it? How do we keep it going?'

''It's such a mixed bag of emotions because I was with that guy every single day... To go back to the same stages, to the same sets, slightly altered with a new President obviously, but to go back to those sets and all of a sudden be with completely different people, it was a strange feeling.

''I don't even know how to put it into words because you know one thing for so long and then all of a sudden it's a completely different world you're living in.

''There's obviously a million emotions that I went through, that I processed during this whole thing. I don't want to talk too much about it because it was heartbreaking in so many ways.''

And Michael admitted he's still coming to terms with the allegations against his co-star, and revealed he hasn't spoken to him since the claims were first reported.

He said: ''All I know is what I hear. But I don't know. It's tough. You go from talking to someone often to not at all, and in any profession, in anything, circumstances removed, what happened removed, it's strange ... and I'm still processing. I haven't formulated any opinion, and I haven't talked publicly about it. This is the first thing I've ever said. I think I'm still going through a lot, processing the whole thing. It's tough.''