Gavin and Stacey viewers have only just spotted huge blunder in Christmas finale episode

Warning: This article contains spoilers for Gavin and Stacey: The Finale

Gavin and Stacey fans have spotted an 'error' in the final episode of the popular sitcom, which aired on Christmas Day.

Viewers have been left in tears over the concluding special, with many describing it as 'flawless' and 'perfect'.

The hour-and-a-half-long episode followed on from the events of the 2019 Christmas special, and tied up a number of loose ends among the main characters of the series.

For example, viewers found out that after Nessa (Ruth Jones) got down on one knee and ask Smithy (James Corden) to marry her five years ago, turns out that Smithy had never given Nessa a 'yes' or 'no' answer, instead going on to get engaged to Sonia (Laura Aikman) instead.

At the end of the final episode, Smithy's wedding to Sonia is interrupted when Gavin (Mathew Horne) finally tells Smithy that he - and all the family - think he's making a big mistake.

Fuming, Sonia tells Smithy at the altar that he'll 'never find anyone better' and he responds, explaining: "I already did."

Smithy is, of course, referring to Nessa and the family end up racing to the Port of Southampton on Dave's bus to stop Nessa leaving the UK for a new job.

Smithy rushes to stop Nessa from leaving (BBC)

Fans were overjoyed when Smithy reached Nessa before she left, with many emotional when he got down on one knee and proposed.

However, eagle-eyed fans noticed that the port and surrounding areas didn't look quite like Southampton.

In fact, people now believe the scenes were actually filmed over 100 miles away in Newport Docks in Newport, Wales.

One person wrote on X: "[Finale] was great but as someone from #Southampton, the perception of the port was completely wrong."

While another viewer added: "Superb acting job by Newport Docks, playing Southampton docks on the #GavinAndStacey Christmas special."

And a third said: "Gavin and Stacey was worth the wait, a perfectly written, performed story that fittingly ends the show, and was emotional, funny and surprising. The call backs and returning cast have always been a highlight, but this was a perfect ending. (Although that wasn't Southampton)."

While a fourth added: "Gavin and stacey really tryna gaslight me into thinking that’s southampton docks. I know my city smh."

People believe the final scenes were shot in Newport (BBC)

The location detail hasn't stopped people gushing about the show, however.

A whopping 12.3 million viewers tuned in to watch the special, which surpassed the number of viewers who watched the 2019 Christmas episode.

The special even broke the record for the most watched TV episode in over 10 years.

Tyla has reached out to BBC for comment.