cristin-milioti-himym-200th-episode As “How I Met Your Mother” (CBS, 8 p.m.) nears its end it presents one of its most unusual episodes tonight — its 200th — as it concentrates solely on something they once tried to keep secret: The Mother.

Cristin Milioti was introduced as the Mother late last season, but tonight for the first time the entire episode is from her point of view and what she’s been doing the past eight years the tale has been unfolding (to long suffering children).

“We’re really excited about and proud” of the episode, co-creator Craig Thomas said on a “How I Met Your Mother” set visit two weeks ago.

“Cristin is amazing in it,” Thomas says, “and there’s a lot of fun intersections between her life and our gang.

“Our gang is in that episode, but really it’s her episode, and I feel that kicks off the end game of the season.”

“It was definitely very scary in the beginning, ” Milioti said of joining the long-established ensemble. “I kept thinking they have been together for nine years and I was just coming off of something where we were all together for two years.”

It was the Broadway musical “Once,” for which she was nominated for a Tony.

“That, while not nine, is still a long time being with the same group of people seven days a week and going through all these emotional things and great things and bad things,” she said.

“But I could not have been more warmly welcomed here by everyone,” Milioti said. “Everyone on the crew, literally everyone along the way has welcomed me with open arms, which has made this a dream come true for me.

“I haven’t been here for that long,” she said. “It’s been fantastic and very warm and lovely.”

To prepare to join the cast, Milioti said, “I watched all eight seasons in three months. I did binge on it.”

She hadn’t seen it before, she admitted. “Which means nothing. Because I just saw ‘Pretty Woman’ over the weekend — Julia Roberts is amazing! — But yeah. It does work so well when you see it all together.”