Seeing Double is a British musical-comedy film starring British pop-group, S Club. Written by Kim Fuller and Paul Alexander, and directed by Nigel Dick, the film mostly features songs from the group's album of the same name including "Don't Stop Movin'" and "Never Had a Dream Come True".
The film opens with a creepy Castle in Hollywood and Victor Gaghan an evil scientist creating his clones and chanting the words "S Club, S Club, S Club" and as he says this he is joined by fans awaiting the group as they arrive in Barcelona, Spain for their last show of their tour. After spending the day promoting and performing, the group gets excited about having some time off. Their manager, Alistair however shoots down their joy informing them that they will be leaving for Los Angeles at seven in the morning the next day. At the hotel, S Club ignores Alistair and after they get into their room, Alistair is attacked by the scientist's assistant Susan Sealove.
The next morning, the members of S Club awakens to find Alistair gone and he left them with the bill. Instead of using a credit card that Rachel finds to pay the bill, they use it on pampering themselves and after going bankrupt Hannah thinks she is going crazy when she sees the cloned s club performing live on TV at a nearby cafe. After the others start thinking they are uncanny lookalikes the members all decide to quickly leave the Hotel and fly to LA but suddenly they are busted and throw in jail and get wrongly accused of impersonating S Club and trying to run out on the hotel bill despite telling the jailer they are the real S Club and innocent.
In jail, they learn that the warden likes to dance and to escape, they sing "Don't Stop Movin'" and get to their friend Natalie. She helps them get to LA by disguising them as English World Cup football fans so that they can stop whoever is impersonating them and not get arrested again by the Spanish Police.
In Los Angeles, the group tries but fails to get close to their doubles, so they decide to switch out their Hannah, Rachel and Jon for their copie's Hannah, Rachel and Jon. After getting the clone's to tell them that they are copies, Bradley, Tina and Jo decide to do something about it after tracking down Gaghan based on his recent online purchases of S Club memorabilia including their underwear, only for them to get caught by his goons.
Both sets of S Club are taken back to Eagle Peak, (Gaghan 's secret mountain laborotory) where Gaghan tells to the originals that he is going to take over the world through music because celebrities attract more attention than politicians (as well as the obviously greater appeal in seeing naked singers emerging from the cloning tubes as opposed to politicians). The clones save the band and then both groups have to save all of the clones he has created including clones of AC/DC's Angus Young, King of Rock & Roll Elvis Presley , Will Smith as Men In Black's Agent K, Victoria Beckham (as Posh Spice), Robbie Williams , Eminem, King of Pop Michael Jackson, Elton John, Madonna, George Michael , Pop Idol star Gareth Gates and Groucho Marx of the Marx Brothers . Both S Club's sing "Who Do You Think You Are?" and the original group is able to stop the place from self-destructing whilst the Michael Jackson clone stops Gaghan and Sealove from escaping in their helicopter. Jon then says how they have released a new bunch of cloned pop acts including Britney Spears , Nsync and Nelly Furtado's into the world and that they should be quiet about it. Clone Alistair suddenly appears and tries to kill the real S Club when suddenly the real Alistair knocks him out. Dr Gaghan and Sealove are later arrested and the group wonder what to do with their clones when Alistair reminds them of their very busy schedules.
At the end, the real S Club are seen at the beach and the clones are taking their place. They have decided that the clones will take their place when they want a holiday, and the same vice versa. (It is also mentioned that the clones are getting paid in boomerangs.)The Gareth Gates clone is also seen talking to Rachel and the film ends