Even with temperatures rising, MacFarlane was not alone to celebrate his second full-length feature as castmembers Amanda Seyfried and Charlize Theron joined the festivities along with producer Scott Stuber and Theron's current beau, Sean Penn.
Before the film started, MacFarlane thanked a handful of people including Universal and MRC for greenlighting and joked he had a two-hander with Katherine Heigl and Shia LaBeouf ready to go if they wanted it.
Following the screening, guests made their way to an open parking lot that was styled into the Old Hump's County Fair featuring games, a live band and plenty of Tex-Mex.
MacFarlane's longtime writing partner Alec Sulkin said that though it does get easier to work with MacFarlane and Wellesley Wild because they know each other's styles, there are times they feel their jokes won't connect the way they used to.
"It can get difficult at times because you start thinking whether you are running out of jokes and start asking stuff like, "Should we start making fun of 9/11 or something?" Sulkin said.
(Pictured: Seth MacFarlane, Charlize Theron and Universal's Donna Langley at the "A Million Ways to Die in the West" party)
Related storiesCANNES: Charlize Theron on 'American Express' as Megan Ellison Rebrands Foreign SalesFox Shakes Up Sunday Animation Block in Major Schedule OverhaulWATCH: Red Band Trailer for Seth MacFarlane's 'A Million Ways to Die in the West' 2014 Variety Media, LLC, a subsidiary of Penske Business Media; Distributed by Tribune Content Agency, LLCCopyright © 2015, The Baltimore Sun