Amanda Batula and West Wilson are already fueling fresh "Summer House" buzz before Season 11 even gets underway ... because the Bravo stars were spotted hanging out together at a Montana bar during a wedding weekend.

Witnesses tell TMZ ... Amanda and West were at a small bar in Bigfork, Montana, on Friday night for a wedding welcome party ahead of Saturday's ceremony. We obtained photos of the couple during their night on the town.

We're told the wedding was for Ty Okada -- a former Montana State football player who was teammates with West in college -- Okada now plays for the Seattle Seahawks.

According to our sources, the bar wasn't especially crowded, giving guests a clear look at the Bravo personalities as they mingled and enjoyed the festivities. Eyewitnesses say both Amanda and West were drinking throughout the evening and appeared to be in good spirits.

Our sources also say Amanda did not appear to be pregnant, despite recent fan speculation online, she was wearing a pink wristband throughout the night ... which eyewitnesses say was simply a standard 21-and-over wristband issued by the bar.

The Montana sighting comes as "Summer House" Season 11 is beginning production ... making this hangout across the country notable, being we previously reported the couple would not make it as official cast members this summer after their secret relationship was confirmed -- publicly blowing up their Hamptons-loving friend group.

For now, it looks like these Bravolebrities traded the Hamptons for Big Sky Country ... as cameras get ready to roll without them.