Posh was apparently spurred on by her son Cruz
The fashionista, 34, recorded a voiceover for the cartoon late last year while in LA.
Victoria, whose youngest son Cruz, 4, is thought to have encouraged her to take the part, plays a princess in the episode.
Victoria was a complete pro and finished all her takes in a day, a source tells the Daily Mirror.
She isnt interested in becoming an actress, but voice-over work is something that appealed.
Spongebob is Cruzs favourite show, so he was incredibly excited. Scriptwriters created the role of a posh British princess especially for her.’
Johnny Depp, Scarlett Johansson, David Hasselhoff and David Bowie have also made cameos on the hit show.
The Spongebob Squarepants episode featuring Victoria will air over the summer.
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