The tone in this excellent female buddy comedy takes a sour turn tonight when, in a bitter case of role reversal, Em's nose is seriously put out of joint when the lachrymose Doll (Dolly Wells and Emily Mortimer) steals a key scene in her big movie. And she was only supposed to be mourner number two. They try to paper over the cracks but it's all going a bit All About Eve as Doll gets stars in her eyes - and John Cusack, in a guest cameo, is clearly impressed.

Doll & Em is a six-part comedy on Sky Living co-written by and co-starring the actors Emily Mortimer and Dolly Wells and produced by Mortimer's husband, the actor Allessandro Nivola. There is also the question of the setting and target of the comedy: Hollywood.

It's very hard to escape the smugness that creeps into any LA-based show that is self-satirising. Even something with the British self-deprecation of Episodes couldn't help but trade on the shock value of a major celebrity (Matt LeBlanc) acting as we believe actors to act: spoilt and cynical. And yet, no matter how vile and superficial the stock pool party in the Hollywood hills is made to seem, the overriding impression is: but wouldn't you like to be here?

One such pool party duly made an appearance in the second episode of Doll & Em, which centres on the semi-autobiographical relationship between successful actor Em (Mortimer) and her best friend Doll (Wells), who has come out from England to work as her personal assistant. There were even some major film star celebrities present in Chloë Sevigny and Susan Sarandon. Was it going to be another dose of self-celebration masquerading as oh-so-cool irony?

That it worked a treat was partly because no big deal was made of it. There were no outrageously philistine producers or predatory starlets. The comedy was not in the manner of the party but its manners - the missed air kiss, the curious asides, the desperate passive-aggressive anxiety that goes into maintaining the unspoken hierarchy of stardom.

In truth, the Sarandon plotline wasn't particularly amusing, but the observation elsewhere was subtle yet forensic, like a sensitive but thorough strip search. It was particularly revealing of the intimate competition surreptitiously conducted between female friends.

As both women fell under the rakish spell of a smooth producer called Buddy (Jonathan Cake), they traded sob stories of their dead fathers in a semi-naked battle to be seduced. That we know in real life they are the daughters of the late John Mortimer and John Wells only added to the comedy of unsayable truths.

It's an awkward, funny and deceptively clever confection that is saved from Hollywood hipness by the unmistakable warmth of the complex relationship at its heart. Perhaps it also helps that it's made by HBO.

Doll and Em stars actresses Emily Mortimer and Dolly Wells as exaggerated versions of themselves. Whilst Mortimer will be familiar to most from The Newsroom, as well as countless Hollywood films, Wells' name is less well known. However, most will have seen Wells over the years in one sitcom or another and she's probably best known for her appearances in Star Stories and Some Girls. The loose story of the show sees Dolly split up with her boyfriend and head to America to work as Emily's assistant. Obviously, this balance of power between the pair builds up a tension based on the fact that one is much more successful than the other. Several comic sequences throughout the episode increase these hostile feelings including one in which Dolly can't work out how to use Emily's sat-nav and another where Dolly finds herself inadvertently locked out of Emily's house.

Doll and Em draws obvious comparisons with The Trip, as it features two real-life friends working together and the slight resentment that builds during the show. The difference is that Steve Coogan and Rob Brydon are both well-known and the problems that arose during The Trip made both men question how their careers had gone. Meanwhile, Doll and Em is a lot more one-sided with the former being an almost unrecognisable presence and the latter being an actress whose hit it big in America. Despite Emily's fame though, I just can't buy the fact that she'd be stopped on the street and asked to pose for photos, which is what happened in one scene in this episode. But my main problem with Doll and Em is that it really didn't go anywhere and at the end of the day felt quite inconsequential. I didn't find it funny nor did I identify with either woman and in addition I know exactly in which direction this series is going. Whilst I can see what Wells and Mortimer were trying to achieve with their show, it comes across as a self-indulgent passion project rather than a fairly well-observed comedy drama.

Best mates turned star and assistant Emily Mortimer and Dolly Wells take their comedy alter egos off to a Hollywood party where Susan Sarandon and Chloë Sevigny are among the faces mingling, moving and shaking - and Dolly gets the chance to practise her babysitting skills with disastrous results.

But it's in the after-party hot tub that things crank up a gear as the duo compete for the favours of smooth-talking producer Buddy (Jonathan Cake).

Real-life best friends Emily Mortimer and Dolly Wells pen a tale about best friends Em and Doll, with Doll joining actress Em in LA to work for her when her relationship falls apart. It's all very naturalistic and obviously feels like a real friendship. Funny? Not in the slightest and there's nothing you can glean from it that you won't have from a dozen other shows like it (e.g. Entourage, Episodes, Curb Your Enthusiasm).

Doll & Em (Sky Living) is an interesting one, semi-improvised comedy written by and starring real-life bezzies Dolly Wells and Emily Mortimer, who play versions of themselves. I don't know how far they've distorted themselves. I think - I hope - a lot because they're a bit ghastly; at times it's like eavesdropping on a pair of self-obsessed luvvie types in a Notting Hill restaurant. Except we're in LA so make that Beverly Hills (Doll is working as her actor friend's assistant after a messy breakup).

It's not lol-a-minute, it's in-jokey and in-crowdy (there are appearances by celebrity pals). It's self-indulgent. But self-aware too. And at its heart is an interesting and genuinely touching examination of friendship - the goods, the bads, the power imbalances, the cruelty, the games, the tears, the love - made all the more poignant by their friendship for real.

Oh, and it's good on the paranoid ridiculousness of Hollywood too. What is anyone REALLY THINKING? Plus I took a sneaky peak at the second one too, which is better. See, even though I was a bit annoyed, and I didn't feel it had much to do with me, I still wanted more. That's a good sign.

A comedy that you write and star in yourself sounds suspiciously like an ego trip - and in a sense that's exactly what Doll & Em is. Actress best mates Emily Mortimer and Dolly Wells play fast and loose with the notion of friendship in a sharp relationship power trip that finds Wells (Some Girls) pitching up in LA after a romantic break-up and winding up working as PA to the more successful Mortimer (The Newsroom). It's a clever case of life imitating art, with appealing turns from both Mortimer and Wells mining laughs from what could be a very touchy subject.

Doll & Em on putting their friendship to a screen test

Best mates since they shared bathtimes, how will Dolly Wells and Emily Mortimer get on sharing the screen?

Dolly Wells on Doll & Em

Dolly Wells doesn't know it, but she's on the verge of becoming a real New Yorker.