Josh Radnor, who plays Ted in the hit American sitcom 'How I Met Your Mother', has said that he knew a key element about the series finale from as far back as season one. The actor, who has already filmed the final scenes, was let in on the secret by the show's creators who have always known how the story was going to end.

The actor told The Hollywood Reporter,"I was let in on a big thing [in the] first season [...] I thought they weren't going to do that, and then they said, 'No, we're still doing that." Ambiguous, ey?

What 'that' is exactly we don't know, we have been introduced to the mother already (Cristin Milioti) and know that it's a train station where they finally meet. We've also seen glimpses into their future too, from Ted's marraige proposal, to their ten year wedding anniversary. However, it's been widely speculated that this wife future Ted (Bob Saget) speaks so fondly of, may actually have died by the time he is telling the story to his kids. Millioti has recently said these suggestions were 'insane', while co-creators Carter Bays and Craig Thomas have refused to comment on it. We can only hope it's not true, but the signs are certainly pointing towards it.

On a recent episode, we saw Ted and the mother in a flash forward to 2024, when Ted welled up when she said, 'Come on, what mother misses her own daughter's wedding?'. Along with Bob Dylan's beautifully, sad song 'If You See Her, Say Hello' playing in the background. (Yes, I have examined this is way too much detail), but surely Ted's tears imply that SHE would be the one to miss her daughter's wedding?

Radnor went on to say; "I knew that one big plot thing early, but it wasn't something that I thought about so much as we were going on," he says. "I always tried to remember that the version of Ted I was playing was moving forward and didn't know everything. He wasn't the narrator with the benefit of hindsight. It was always better for me to just read the episodes each week and try to play him as honestly as I could each week. I trusted them that they were going to take him on the right journey."

The final episode of How I Met Your Mother will be aired in America on Monday, and will bring to a close a 208 episode long wait to see how Ted meets the woman he will marry. Filming for the cast finished up on March 1, with Radnor's last scene to mark the end of his nine year role, appropriately being on the train platform with Millioti. The star is still getting his head around it all though; "It was so complicated, I'm still working through it. It wasn't like I left the set and felt completely emotionally resolved about everything. It was a very complete experience the last two weeks, but I didn't know how to process it actually ending."

We're not sure we will know how to process its actual ending either to be honest, as long as we've waited for it...