Tom Ellis says he has been keeping it a secret that he is in "Crisis on Infinite Earths" for months, since he wants to surprise "Lucifer" and "Arrow" fans. He adds that it was not hard to convince him to do a cameo because Vancouver is special to him and he is friends with Constantine actor Matt Ryan.

ET's Katie Krause caught up with Ellis once again, a month after he shut down rumours of his appearance in the CW series in a past interview. The "Lucifer" star revealed that he kept the secret about his cameo for three-and-a-half months. He and Ryan already agreed prior to filming that he would keep his cameo a secret until he actually appears on screen. It took a lot of effort to squash the rumours after people saw him and leaked pictures of him at the "Arrow" set in Vancouver.

"Of course, these days that's not that possible with social media at all. I think there were a few people hanging around the set who noticed that I was there and put stuff out that I was going to be in it, so I kind of was like, 'I would still really like to surprise some people.' So that is why," Ellis explained.

The Welsh star shared that the producers approached him for a cameo in "Crisis on Infinite Earths" before filming began for "Lucifer" Season 5 in September. It was an easy yes for the actor because Vancouver holds a special place in his heart. It is where he filmed Seasons 1 and 2 of his Netflix series. Returning to the city gave him a chance to see his friends there.

He added that he has always wanted to see Lucifer as a DC character. To have that opportunity by joining the Arrowverse was a great welcome. He and Ryan also toyed around with the idea before, and Ellis claimed they "manifested" Lucifer's cameo in "Crisis on Infinite Earths."

In the end, Ellis hoped that he did not let down his "Lucifer" fans when he denied the rumours back then. He admitted that he only wanted to surprise the viewers given the number of characters confirmed to appear in "Crisis on Infinite Earths." He wanted the Devil's cameo to be a surprise and a "nice little Easter egg."

Netflix Series "Lucifer"
Tom Ellis reprises his role as Lucifer Morningstar in "Lucifer" Season 5.