They say that good things happen in threes (or is that just bad things?), and according to the New York Post, "How I Met Your Mother" actress Sarah Chalke is pregnant--making her the third actress on the sitcom's set with a bun in the oven.

Sarah Chalke's pregnant costars on "How I Met Your Mother" include Alyson Hannigan and Cobie Smulders. What's also curious is that on the set of another show in which Chalke appears, "Scrubs," Judy Reyes is also pregnant. Is Sarah Chalke pregnant by association? Is there something in the water?