The Tropic Thunder star proposed to Pill over the Christmas holidays (Dec10), but admits he was wracked with nerves when he presented the actress with a 180-year-old Victorian ring.
He tells ET Canada, "When I gave it to her, I just said, basically, 'S**t or get off the pot.' I said, 'F**k it, will you marry me?'"
Baruchel met Pill, who's starred in Milk and Scott Pilgrim vs. the World, while filming upcoming hockey film Goon.
The couple plan to tie the knot in September 2012.