Isla Fisher & Ed Helms Joining Cameron Diaz & J-Lo In ‘What To Expect When You’re Expecting’

Kristen Wiig & Matthew Morrison Forced To Drop Out Due To TV Schedules

Update: Reps for Ed Helms have told us he will not be in the film.

Outside of megahit “Knocked Up,” the ups and downs of pregnancy haven’t really provided much mirth on the big screen over the years: when child-carrying is portrayed on screen, it tends to be closer to “Rosemary’s Baby” than to, say, “Nine Months.” But with “Bridesmaids” proving to be one of the biggest hits of the year, the female-driven comedy is back in in a big way, and Lionsgate is hoping to cash in with their big hope for next summer, “What To Expect When You’re Expecting.”

Based on the perennially popular advice book for the soon-to-be-parents, the film, penned by Shauna Cross and Heather Hach, will follow the template that’s proven so popular in the likes of “Valentine’s Day” and “He’s Just Not That Into You,” following half-a-dozen couples all preparing to bring new life into the world. Cameron Diaz has been set for the lead for a while now, and last night Jennifer Lopez looked to be getting in on the action as well. Now Vulture, who seemed to have the Lopez scoop before Deadline, also suggests that two names familiar from recent comic hits are joining the film as well.

As well as Lopez, the site suggests that Isla Fisher, who somehow hasn’t quite become the giant star she looked to be after “Wedding Crashers” (we can all blame “Confessions of a Shopaholic” for that one), is set for a supporting role, and that Ed Helms, who’s had a colossal hit with “The Hangover Part II,” is in talks to play one of the expectant fathers.

However, the studio and director Kirk Jones (“Nanny McPhee“) haven’t had their way with everyone: “Bridesmaids” star Kristen Wiig was the first choice for Fisher’s role, but the actress passed owing to her commitments to the next season of “Saturday Night Live” — which answers at least one of the questions we were asking last week, as to why Wiig hasn’t yet capitalized on the success of her giant smash hit. Similarly, and despite what Deadline reported yesterday, “Glee” star Matthew Morrison was being courted for a part, but supposedly his commitments to that show, and to the promotion of his solo album, look unlikely to make that work.

It’s a little fishy in both those cases, considering that Helms is tied to “The Office” for the next season as well, but still seems to be involved (and the actor managed to shoot “The Hangover Part II” while remaining involved in the show) — it seems likely that Wiig, at the very least, simply wasn’t keen. And we’re not surprised: playing comic relief to Cameron Diaz would have been a waste of her talents.

Filming begins in four weeks, and Lionsgate has already bagged the “Bridesmaids” slot next summer, with the film opening on May 11, 2012, so we’d expect to see the rest of the cast come together shortly.