How did Ncuti Gatwa's bi-generation go down with Doctor Who fans?

Ncuti Gatwa's 15th Time Lord made a wild entrance in Doctor Who's third and final 60th anniversary episode 'The Giggle'.

Airing on BBC One on Saturday night, the action built up to a skyline stand-off between David Tennant's 14th Doctor and The Toymaker (played by How I Met Your Mother's Neil Patrick Harris), with his nemesis forcing the TARDIS-dwelling hero to regenerate for the last Trilogic Game.

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Ripping up the Whovian manual, Gatwa's Doctor bi-generated; withdrawing himself from his predecessor's body and able to exist at the same time, much to their shared disbelief.

Traditionally, one Doctor will regenerate into another, with their replacement taking on the mantle of universal explorer alongside a companion. This time however, Tennant's incarnation didn't fade away and instead settled for a life on Earth with Donna Noble (Catherine Tate).

Quite a bold move, then, which welcomed mixed reactions on social media as the scene played out.

"I'm fine with bigeneration as a zany new sci-fi concept - fans will have baulked at regeneration once too and that's now rightly hailed as the show's saviour - but the idea that no Doctor ever truly stops existing somewhat lessens the drama of any future departures," pointed out one fan.

"THIS MEANS DAVID TENNANT CAN EASILY RETURN FOR MORE SPECIALS IN THE FUTURE" and "Sad to see the last (for now?) of David Tennant and Catherine Tate. And - wow - Ncuti Gatwa really hit the ground running. Buckets of charisma. Doctor Who is in safe hands," wrote two more.

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Further divided responses read: "The Giggle was so stupid (bigeneration! sure!) and silly and inventive. the best ending for Tennant's doctor - finally able to enjoy life with [his] best mate. Ncuti shooting out into the stars with a smile on his face", "Ncuti's Doctor is a SASS icon I love him already", "I'm a bit iffy with the bigeneration but Ncuti Gatwa was fantastic" and "I think bigeneration is an interesting concept, and a great send off for David Tennant - but my fear is that it will completely undermines Ncuti Gatwa's Doctor. I think duplicating the TARDIS is a big part of that problem."

Doctor Who will return on Christmas Day on BBC One at 5.55pm.

Watch: The moment Sex Education star Ncuti Gatwa regenerates as Doctor Who's Time Lord