The actor departed the BBC sci-fi drama last year, but told Digital Spy that he would be open to making a cameo in a special 50th anniversary episode.
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"I'm so busy at the moment that I don't know if I'd be able to," said Darvill, who will appear opposite fellow Who veteran David Tennant in ITV's new crime drama Broadchurch.
"But I'm very loyal to Doctor Who - I saw Steven Moffat recently and I think he's brilliant. He's one of those people that if he ever asked me to do anything, I'd do it."
Darvill also revealed that he had watched and enjoyed Doctor Who's 2012 Christmas special - the first episode to air following his character Rory's departure.
"Yes, I did see that - I thought it was great," he admitted. "The show's constantly growing - it's quite nice watching it and not knowing what's going to happen!"
Broadchurch begins on Monday, March 4 at 9pm on ITV.
> Arthur Darvill Broadchurch Q&A: 'I have great scenes with David Tennant'
Watch the trailer for Broadchurch below: