Media playback is unsupported on your device Media caption You’ve all heard of Andy and Jamie... now it’s time to meet Duncan Murray.

The comedian behind a spoof video claiming Andy and Jamie Murray have a brother who can't play tennis says he is amazed people thought it was real.

Chris Forbes plays Duncan Murray in the video, which has been watched more than three million times on social media.

Judy, the mother of the two tennis champions, appears in the short film saying people ask why she does not talk about her other son, Duncan.

"Then they meet him and they understand," she says.

Image caption Duncan (Chris Forbes) appears alongside Judy Murray in the video

The video, from BBC Scotland's Short Stuff, is clearly played for laughs but Forbes has been surprised by how many people have said they were not sure if it was real.

He told BBC Scotland's The Edit: "It has been quite odd. A lot of people think Duncan is real. While that is quite concerning, it is also quite sweet.

"People have really taken this fictional being to their heart. It's nice to see that people will care for somebody even though he doesn't exist."

Forbes said he'd had the idea for the "other Murray brother" for quite some time.

He said: "I'm a big fan of the Murray family in general - the whole family.

"I like tennis and I've always had this weird idea that it would be funny if there was another sibling that no-one knew about, just a real black sheep of the family that had no sporting prowess whatsoever and just what it would be like to grow up in that family.

"I wrote it thinking it would be a funny idea to concentrate on this guy, Duncan, and hoped that Judy might be interested in being part of it, but I thought it would be funny to even make it without her."

Image caption Duncan sitting behind his famous brothers Jamie and Andy

Forbes said BBC Scotland sent the script to Judy Murray and she loved the idea.

The stand-up comedian, who is also known for playing PC Charlie MacIntosh in BBC Scotland comedy Scot Squad, said it was "very surreal" acting with Judy and pretending to be her son.

"She was a natural," he said.

"Her turn of phrase was perfect. Her delivery was spot on. I've worked with a lot of actors who have trained for years and she put a lot of them to shame but I think that came from her enjoyment of the sketch."

Forbes said Judy got so involved she actually started throwing in some of her own ideas.

"One of the bits in the final video where she has a sponge ball to hit Duncan - that was all Judy Murray," he said.

"If anything, sometimes unfairly, I think people think she was too straight-faced but one day they might get to see these out-takes. There was more laughter than straight face."

And will we see more of Duncan?

"I can't really say anything too much but I think and hope that Duncan may reappear," he said.

The Edit is on the BBC Scotland channel at 19:15 on Sunday 7 July and on the iplayer