Plot very similar to Buona Sera Mrs Campbell

The first time I watched this it was because I love ABBA and have always liked Pierce Brosnan and Meryl Streep and was curious how they'd do in a musical! My initial impression was that while the story seemed contrived to just incorporate the great music, Mr Brosnan and Ms Streep should not quit their day jobs(though they were quite brave for the effort)and the duet between her and Amanda is so touching,esp their sweet harmony-and who cannot appreciate the closing numbers in the ABBA costumes?!
I was sharing an apt at the time with someone who LOVED IT and the more I watched it the more I found many positive moments that outweighed the negatives and became addicted to it.
Then, today TCM aired Buona Sera Mrs Campbell,a movie about a single mother with a teenage daughter living in a small Italian village, who learns,to her dismay,that there is a reunion of WWII American veterans,3 of whom she dated and has been receiving money from because they all think they're the father-but she doesn't know which one truly is(sound familiar) and she'd always told her daughter that her father was a fictitious Eddie Campbell, who died during the war.
It's a comedy that,though considered 'racy' was well received for both the story and Miss Lollabrigida- of her male costars, Peter Lawford, Phil Silvers and Telly Savalas-Mr Lawford is the only one of really leading man status, also having the cachet of being part of the infamous "Rat Pack".
But there are so many scenes that are so similar to Mamma Mia,it almost seems impossible that it didn't inspire it.
So if you aren't an ABBA fan but like the story, watch Buona Sera Mrs Campbell. For me, I prefer the musical.