People who you thought were the same person.

[thraxx]

Though weirdly, the old couple on the bus, the husband was Reginald Tsiboe, Bobby Farrell's replacement in the early 80s lineup of Boney M, who unlike Farrell, actually sang.

Crimey - I know Reg. He's a lovely chap and he has indeed got a lovely voice. He doesn't look like the old couple on the bus though.

[Icehaven]

Rupert Grint and Domhnall Gleeson. To be fair I actually just thought Gleeson played Harry Potter's friend and didn't know Rupert Grint even existed.

[poodlefaker]

I thought John Hannah and James Nesbitt were the same person for a while; they seemed to appear at the same time. Similarly John Simm and Simon Pegg.

[George White]

I thought John Hannah and James Nesbitt were the same person for a while; they seemed to appear at the same time. Similarly John Simm and Simon Pegg.

Well, they play up the latter in Spaced, don'tthey, that Simm is like a neater, posher Tim.

[Clatty McCutcheon]

Anna Richardson and Dawn (O) Porter. I'm easily confused by vaguely similar hairstyles.

[Bobtoo]

Kevins Bacon and Spacey. I still refuse to believe they are two different people.

[Cuellar]

My father and Father Christmas.

[poodlefaker]

Annie Leibovitz and Fran Lebowitz

[Voltan (Man of Steel)]

Dick Van Dyke and Danny Dyer. There's only a superficial physical resemblance but the voices..!

[olliebean]

Frank Bough and Brian Clough.

[bim sherman shirts]

https://www.youtube.com/watch?v=rfpxV6AIpLk

When I was five I saw this clip of Alvin Stardust on TOTP and assumed Elvis Presley was the same person.

Also, around the same period my mum and dad were watching news coverage of the Iranian embassy siege and I took one of the gunmen to be Noel Edmonds.

[Icehaven]

Anna Richardson and Dawn (O) Porter. I'm easily confused by vaguely similar hairstyles.

Oh ffs. I really thought him out of IT Crowd's wife had dumped him and gone gay with Sue Perkins.

[Icehaven]

Fran Drescher and Janice from Friends. I'm not sure if I thought they were the same person or just that the Janice actress's name was Fran Drescher because they've done a mickey take of her a few times on Family Guy and they've got similar voices.
Edit: just googled it and there's even a Mandela effect thing about it.

[ColinPopshed]

Haha this is a stupid one, but when I was really young (5 or 6 I guess) I remember wondering if Tony Hadley from Spandau Ballet was the same person as Gordon Burns, presenter of The Krypton Factor.

I mean, they both had brown hair...

[alan nagsworth]

I thought I was the same person but then I realised that I had changed, irrevocably. Puberty's fucking mental.

[Noonling]

When I was young: Anthea Turner and Princess Diana. Then Princess Di died and I could finally tell them apart.

[St_Eddie]

Haha this is a stupid one, but when I was really young (5 or 6 I guess) I remember wondering if Tony Hadley from Spandau Ballet was the same person as Gordon Burns, presenter of The Krypton Factor.

I mean, they both had brown hair...

Racist.

[Cuellar]

I used to think Frank Zappa was the poet C H Sisson

[Colin Sanction]

Fran Drescher and Janice from Friends. I'm not sure if I thought they were the same person or just that the Janice actress's name was Fran Drescher because they've done a mickey take of her a few times on Family Guy and they've got similar voices.
Edit: just googled it and there's even a Mandela effect thing about it.

Don't you mean Mugabe Effect?

[NurseNugent]

When I was reading Peter Armitage's obituary, I wondered why his role as Jonny Brigg's dad wasn't mentioned when it dawned on me that it was because that was Leslie Schofield. To be fair, they have both played Sue Devaney's dad. 

[a duncandisorderly]

these two lasses-

[kalowski]

Frank Bough and Brian Clough.

See also: Ellen Barkin and Alan Arkin

[Satchmo Distel]

Alan Arkin and Alan Alda

Richard Widmark and Joseph Cotten

Lee Van Cleef and Lee Marvin

[George White]

Then, Twilight's Last Gleaming and the Man Who Shot Liberty Valance will confuse you.

[Flatulent Fox]

Jeremy Beadle and Tim Curry.
                                                     The Beadle was particularly good in 'The hunt for red October',but this time HE got pranked!

[Phil_A]

Rachel Blanchard (Nancy from Peep Show) and Rachel Keller(Syd from Legion)




Just to confuse matters they have also both appeared in Fargo, but not at the same time.

[Lost Oliver]

Kieran Trippier is a smaller version Tommy Robinson.

[DrGreggles]

I once heard John Gregory on the radio and could've sworn it was Glenn Hoddle.

Similarly Martin Peters and

[Andy147]

Paul Bown and Paul Shearer.