What happens when two of the most accomplished actors working, one Irish the other Irish American, meet onscreen? Find out when Chris O'Dowd and Melissa McCarthy star in The Starling on Netflix this weekend.

The Starling is the new comedy-drama starring Chris O'Dowd and Melissa McCarthy about a married couple trying to find their way past the tragic death of their toddler, which has completely unmoored their lives.

Yes, I did call the film a comedy-drama but I was surprised as you to hear that anyone thought this wrenching premise suggested a barrel of laughs or even an occasional indulgent smile. McCarthy is best known for raunchy side splitters like Bridesmaids (her first film with O'Dowd also co-starring) or for memorable character dramas like Can You Ever Forgive Me? so The Starling is an odd choice for both seasoned Irish and Irish American actors, who are hardly short of interesting scripts to consider. 

But you can see why O'Dowd, 41, signed up for The Starling in the first ten minutes. A portrait of how two people in love find their way back to themselves and each other after a life-changing tragedy, on paper, it's a perfect vehicle for both his and McCarthy's screen skills.

The plot of The Starling is straightforward: Lilly and Jack are two happily married people who suffer a loss that they respond to differently. Jack checks in to a mental health care facility as Lilly toughs it out at home, going to work and trying to stay focused.

But soon we see Lilly staring into space in the endless food aisles at work, distracted by the grief she won't allow herself to confront. Worse, she starts absent-mindedly stapling five cent stickers onto every piece of produce that she comes across, setting off a shopping frenzy, overwhelming the checkout staff, and angering the management who can see her mind isn't on her job.

McCarthy, 51, is one of the most convincing screen actors currently working and she sells her heart-shot character from the first scene. Taking weekly treats to her stricken husband in the psychiatric ward she clearly gives no thought to herself, even when others are explicitly telling her that she's not holding up as well as she thinks. 

It's when she sits in on one of her husband's group therapy sessions that things come to a head. Finally, her anger erupts when she's told he would prefer not to see her for a little while because it's a painful reminder of their loss, which is a request that makes her reconsider who she is to him and why she has been putting herself out for a man this selfish.

McCarthy eats up the screen, allowing her fury and sadness to finally emerge and overwhelm her, to the point where her husband's worried therapist suggests a counselor is warranted, giving her only one name.

Larry (Kevin Klein) was a onetime therapist who has inexplicably decided to pursue veterinary medicine, so that is where Lilly first meets him. Between all the dogs in heat and cats in stitches, she pours out her heart to this wise but wary healer. Klein is sympathetic but he thinks she's resisting the real issues. Her husband may be in bad shape but at least he is facing the tragedy, Larry says. When will you start, he wonders, and we the audience do too.

The film's title comes from a standoff battle Lilly is having with a territorial bird who has built a nest in her garden. When Lilly tries to plant some new vegetables to take her mind off her troubles she is startled to find herself being dive-bombed by an enraged starling who doesn't welcome her presence so near his partner's nest.

We are in the presence of a metaphor so hokey even Lilly mentions at one point that it's a little on the nose for a woman in her particular predicament. Starlings mate for life and they protect their nests with all they've got, a stand-in for the sorrow that has fallen on Lilly's home.

O'Dowd does well with this tearjerker format, injecting as much real-world pathos as this weirdly sentimental script will allow. But even his skill – and it is very considerable – cannot stop this increasingly cloying film from getting bogged down in its own good intentions. 

McCarthy decides the way to ward off the starling is to wear an American football helmet, allowing some truly misjudged comedy moments to derail this otherwise carefully observed story of grief and its aftermath.

Klein is increasingly at sea as a phoned-in wounded healer, but his self-help appearances are so treacly that it undermines his character and the film, turning something as searing as a premature bereavement into a take it on the chin tale where our plucky heroine finds the strength to go on.

Call it the Oprahfication of emotions. Just like the talk show queen, this film apparently wants you to Learn Something about yourself so it hits you as hard over the head as that starling hits McCarthy's football helmet. At this point the film passed beyond gentle cringe into a full-on patronizing insult, losing my interest as it inspired my scorn.

O'Dowd and McCarthy are not at fault for this narratively confused film, it's mostly the fault of the script and the direction, which features some of the least convincing (computer-generated) onscreen birds since the era of Alfred Hitchcock. 

The film gently reaches for our emotions but then it thrashes them onto the canvas in the manner of WWE. I personally hope you never experience the kind of loss that the unfortunate couple here does. But equally, I hope that if you do you won't be subjected to the silly sermonizing that passes for insight here, or if you do I hope some angry starlings descend on whoever dares to subject you to them.

The Starling wants to remind us that if you can only get through the five stages of grief it may eventually be alright. But it does so in a film so sweetly saccharine that you will fear for your molars around the midpoint.

The Starling debuts on Netflix on September 17.