From left, Stephen Merchant, Warwick Davis, Ricky Gervais. ‘Life’s Too Short’ (30 minutes) premieres Sunday at 10:30 p.m. on HBO. (Ray Burmiston /HBO)
TV critic

In “Life’s Too Short,” a mostly tepid, half-hour comedy series premiering Sunday night on HBO, the once-brilliant Ricky Gervais and Stephen Merchant return to the same vat of mean-spiritedness that served them so well on “The Office” and “Extras.” The two are masters at cooking up seemingly improvised moments that depict the human condition at its most painfully awkward.

Cue the dwarf!

Warwick Davis — a British actor who played Wicket the Ewok in 1983’s “Return of the Jedi” and co-starred in 1988’s “Willow,” among other roles — plays a version of himself here, much the way Larry David plays the distasteful “Larry David” of HBO’s “Curb Your Enthusiasm” or Matt LeBlanc plays the unctuous “Matt LeBlanc” of Showtime’s “Episodes.” There must be something cathartic about playing a nastier, alternate version of one’s self. Otherwise, why would so many celebrities jump at the chance?

Warwick’s celebrity stretches the definition of the word (depending on how many “Star Wars” conventions you’ve found yourself attending), which is “Life Too Short’s” central premise: Having tasted stardom as a teen, Warwick is now a delusional 41-year-old coasting on his tenuous Industry connections, charging 25 pounds for a signed picture and grubbing around for small (er, bit?) parts in any film project. In yet another exercise of the trite mockumentary format, a film crew is following Warwick around as he looks for work, an exercise in show-biz hubris that hasn’t aged well since the glory days of Lisa Kudrow’s “The Comeback,” which aired seven years ago.

Warwick’s wife is in the process of divorcing him, and his accountant tells him the money has dried up. Warwick runs a talent agency for little people, who all justly accuse him of keeping the plum job leads for himself while they’re all forced to take gigs as human projectiles in pub bowling tournaments and the like. (Rosamund Hanson, one of the show’s bright spots, plays Warwick’s inept secretary.)

At some point in each episode, Warwick swings by the posh offices of “Ricky Gervais” and “Stephen Merchant” (played by Gervais and Merchant). No matter how high up they move the door buzzer, Warwick still manages to get in. Weirdly seated at a table side-by side whenever Warwick visits, the two men are repulsed by Warwick’s smarminess but also like to prod his disproportionately enormous ego. It’s not unlike the claws they sharpened on Karl Pilkington, who co-stars with them on “The Ricky Gervais Show,” in that their disdain for Warwick borders on pathological fascination.

In fact, almost everything about “Life’s Too Short” somehow echoes pieces of all of Gervais’s previous TV work, which makes this show seem particularly limp. Like “Extras,” the show leans too heavily on celebrity cameos, where even the funniest lines barely encourage a smirk. Helena Bonham Carter, as herself, has a meltdown on the set of a period drama when Warwick is hired as a stand-in for a child actor. Liam Neeson comes to the Gervais/Merchant compound while Warwick is there (“We worked on ‘The Phantom Menace’ together,” Warwick gushes, to no avail), hoping to enlist Gervais’s help in his disastrous attempt to try comedy.

Another episode brings in Johnny Depp, who hires Warwick to advise him for his next Tim Burton character, Rumpelstiltskin. Depp forces Warwick to shuffle, dance, scream and stand in a toilet.

Savvy viewers will quickly ascertain the true reason Depp is here: Soon enough he and Warwick are in Gervais’s office for an utterly contrived confrontation that references Gervais’s impolitic remarks about Depp and other stars during the 2011 Golden Globe Awards show. This is where it will dawn on you that “Life’s Too Short” is really just a meanderingly unnecessary walk through the mirrored tunnels of Gervais’s self-regard. It purports to be about a down-on-his-luck dwarf who craves exposure, when in fact, it’s just as much about a talented actor and producer (Gervais) who’s overexposed and at the end of his creative rope. Strangely, this may well be the show’s subliminal intent.

All of which makes it hard to focus on what’s curiously good about “Life’s Too Short”: Warwick Davis.

From chronically tumbling out of his enormous SUV when he opens the door to ignoring the constant stares he gets while walking down the street, Davis gracefully, gleefully digs into his despicable character. Though the script is filled with galling “midget” references and other insults, it’s all in the service of irony. Somewhere in here, we’re meant to absorb a nuanced message about the hurt of Warwick’s constant marginalization in society, which no amount of success can fully relieve. One can’t help but wonder how good this show might have been if Gervais weren’t in it at all.

Life’s Too Short

(30 minutes) premieres Sunday at 10:30 p.m. on HBO.