Williams: I had no clue about Segel
The My Week With Marilyn actress - who has a 7-year-old daughter, Matilda from her relationship with the late actor Heath Ledger - has been dating How I Met Your Mother funnyman Jason for around a year.
"I didn't actually realise who he was before I started dating him," she admitted to InStyle magazine.
"I mean, I saw the Muppets movie, and I thought, 'Oh, that's cute,' but the truth is I didn't realise he made a lot of very popular, funny movies or was on a TV show."
She added of the 6'4" beau: "I didn't realise he was so tall... I thought, 'Hey, man, you're cramping my style!'
"I tried wearing wedge heels for a while to compensate, but it wasn't me and I just gave up."
The former Dawson's Creek star also revealed she's never been happier.
"The other day I was out there all bundled up and the sun was shining and I realised I was smiling in a way I hadn't in a long time," she added.
"The roses in my cheeks weren't from make-up for once. It was a perfect moment."