It seems that "Doctor Who" producers are on the prowl for their own Hollywood guest stars after Sigourney Weaver made a cameo on "Doc Martin", reported by Digital Spy.

First on the list of actors that they want on the show is Tom Hanks, who current Doctor Peter Capaldi revealed he was prompted to ask himself. Speaking to ITV's "Good Morning Britain", "I think Doctor Who is a great venue for any kind of actor," Capaldi said.

"Funnily enough, they were trying to persuade me to... I was working with Tom Hanks last night and the producer was on to me saying, 'Try and persuade Tom to come and be in the show'," he added.

But did Hanks agree to be part of the British sci-fi series? Unfortunately not. "I did have a word with him, but he is very busy at the moment," Capaldi shared.

With a Tom Hanks guesting out of the question, Capaldi noted that there are other people he would like to see at least do a cameo, although he'd prefer rock stars over actors. "I think it would be good to have some rock stars; I'd like to see Keith Richards or David Bowie," he shared.

However, while he's making a list of the people he'd like to see in the show, there is one actress he will be saying goodbye to.

Evening Standard UK reported that the actor made an appearance at the recent "Doctor Who" festival, where he paid tribute to his departing companion, Jenna Coleman, whose character, Clara Oswald is leaving the show after three years of adventures in the TARDIS.

Coleman, who started as the Doctor's companion since the 11th reincarnation with Matt Smith, has helped Capaldi transition into the Time Lord. He shared about Coleman, "She is someone who looked after me from the day I arrived. She made it so pleasant and we have so much fun."

Sitting with Capaldi, as well as co-stars Michelle Gomez and Ingrid Oliver, and show runner Steven Moffat, Coleman told the audience at London's ExCel Exhibition Centre that she was emotional about leaving the "whimsical and big" series.

"Steven and Peter said these lovely words [at the wrap party for the second series]. I got on the stage with these things I wanted to say and all I could say [in a strangulated voice] 'thank you'. It was all I could get out," she added.

It's always been noted that the Doctor's companions are female, so Tom Hanks, Keith Richards or David Bowie, despite Capaldi's eagerness to work with, will not be the Time Lord's next sidekick. Do you have any idea who the next companion will be?