Note: Big spoilers follow for How I Met Your Mother: Season 8 finale. Look for an Update to this story at the bottom of the page. How I Met Your Mother creators/executive producers Craig Thomas and Carter Bays had hinted at some big changes to the show in Season 9, which will be the final year, and now we now what that means. How I Met Your Mother: Season 8 Finale Review In How I Met's Season 8 finale, the show took a massive step by finally introducing the Mother of the title, played by stage actress Cristin Milioti (Once). In a statement, Carter Bays said, 'It was a pretty big umbrella to fill, casting the title role in a series that's been on the air for eight years. And yet Cristin Milioti is, against all odds, exactly what we were looking for. She made us laugh on 30 Rock, she made us swoon in Once, and her ukulele skills are no joke. We're thrilled to welcome her to the How I Met Your Mother family, and look forward to getting to know her '� and the ...