The toe tapping compositions by Brett McKenzie keeps this lively, yet Muppets Most Wanted is let down by questionable casting and a ho-hum plot.

Shocking as it may sound, the key to a successful Muppets project is not necessarily The Muppets themselves, but what their human co-stars bring to the party. Whether it is The Muppets Show or The Muppets Christmas Carol, it is those made of flesh and blood that draws us into this world of singing frogs and karate chopping pigs that the legendary Jim Henson created some 60 years ago.

The largely successful 2012 “re-establishing” The Muppets capitalised on just that fact. Directed by James Bobin (who returns behind the lens here), The Muppets wisely starred Jason Segal (who also co-wrote) and Amy Adams in the lead roles, bringing a joyous spirit that enhanced the Mup-tastic atmosphere to bubbly delights.

Unfortunately neither Segal nor Adams return in Muppets Most Wanted, a sequel (the eighth in the franchise) that continues moments after the 2012 Oscar winning hit ended, with Kermit, Miss Piggy, Fozzy and the rest of the gang contemplating there next move.

Enter Dominic Badguy (Ricky Gervais), the “#2 Most Dangerous Criminal in the World” who poses as The Muppets tour manager so he can gain access to some of Europe’s most valued artistic treasures.  

Badguy’s partner in crime is the dastardly frog Constantine, the “#1 Most Dangerous Criminal in the World” with a near identical resemblance to Kermit, save for a mole and an Eastern European accent that’s a mix of Borat and Count Dracula.

A switch-a-roo has Constantine leading The Muppets while Kermit is thrown into a Siberian gulag. It is the scenes within the icy prison that are the films best, with Tina Fey bringing the funny and an impressive set of pipes (along with a thick Russian accent) to the role of gulag warden Nadya.

Fey’s turn has just the right amount of pop to hang with Kermit and the gang. Funny too is the sight of Hollywood tough guys Ray Liotta and Danny Trejo croon along to Brett McKenzie’s funky, soulful and – above all – playful compositions. McKenzie’s Flight of the Conchords co-star Jermaine Clemente joins in on the fun as the leader of a prison gang.

Oddly, for a film packed with movie stars in cameos ranging from Christoph Waltz doing a waltz, Salma Hayek running with the bulls, and Tom Hiidleston playing an escape artist, all of the combined don’t bring anything to the table.

Even worse is the casting of Gervais, for while the British comedian can be funny, his humour thrives upon awkward humiliation and dry cynicism, hardly the joy rousing rabble needed in a Muppets movie (or indeed any other family film).

It is McKenzie’s songs that are the true star and saviour in Muppets Most Wanted. Should another Muppets movie be in the works, Disney is wise to lock McKenzie in for a swift return. But more important, they must cast the right actors who bring something more to these Muppets shows than a name above the marquee.