WARNING: This article contains spoilers for Doctor Who season 12. Read at your own risk.

A familiar face appeared in the recently-aired episode of Doctor Who season 12. Many were shocked seeing John Barrowman appearing as Captain Jack in "Fugitive of the Judoon." It's been a long time since they've last seen him, but fans were happy he's back within this world.

No one anticipated Barrowman's cameo in Doctor Who season 12. In fact, the actor shared how he kept his appearance a secret. In an interview with AV Club, the actor revealed what he did to keep his arrival on the show under wraps.

Barrowman said he's covered in black sheets when going to work and would be sitting in the back of the car. The actor also shared he was told to wear a hoodie. All of his scenes were filmed at the Cathedral in Bristol, so whenever he goes there, he's surrounded by people with umbrellas.

The actor said that his mom and dad, his sister, and his husband were the only people who knew about his appearance in Doctor Who season 12. Barrowman then revealed how he made an excuse to social media, as people wondered why he's in Cardiff - Doctor Who's shooting location.

Barrowman started making excuses by posting on his Instagram about renovating one of their properties. And after a couple of days, he did renovate his flat. He thought he might just do it, as he already said it on social media. He was able to share stuff about it and kept his appearance a secret.

Since Barrowman's appearance on Doctor Who season 12 was already revealed, some were wondering whether or not he's coming back again. According to CarterMatt, there's a possibility the actor will be returning, but it all depends on the right timing.

Meanwhile, the next episode will see Team Tardis investigating mysterious cases. They'll be searching for clues to find out the connection between birds behaving strangely in Peru, between US naval officer who washes up on a Madagascan beach, and a missing astronaut in the Indian Ocean.

It seems like these three cases have something in common and the team will find that out. But then, the mission wouldn't be easy for them as there's a big risk for them. While doing their best to solve these cases, they could be facing challenges along the way.

Doctor Who season 12 airs every Sunday on BBC.