Neil Patrick Harris makes surprise appearance in season premiere of 'How I Met Your Father'

“How I Met Your Father” pulled off quite the casting coup in its season two premiere when “How I Met Your Mother” star Neil Patrick Harris made a surprise appearance.

The episode, which became available to stream on Hulu on Jan. 24, drew to a close with Hilary Duff’s Sophie Tompkins lamenting to her best friend Valentina (Francia Raisa) that she had hit “rock bottom” in her love life after she “blew it with three guys in 48 hours.” Her future self (Kim Cattrall), though, hinted that was actually not the case.

“I was wrong,” she said. “Rock bottom wouldn’t come until later that year.”

We then saw present-day Sophie driving a car sometime in the near future while leaving her mother a message.

“I think I’m dating my dad,” she said in a panic.

She then hit another vehicle and got out of her car, as did the driver of the other vehicle, revealing himself to be Harris.

“Dude,” he says, while buttoning his suit — which Barney always wore on "How I Met Your Mother" — just as his back bumper fell off. Fans of the original series will also remember Barney had to learn how to drive in the original series, so it's unclear if that will resurface.

It’s not made explicitly clear that Harris is portraying Barney, and Cattrall’s future Sophie played it coy when her son asked who the man was.

“We’ll get there soon enough,” she said.

Harris is the second main cast member from “How I Met Your Mother” to appear in “How I Met Your Father.” Cobie Smulders returned as Robin Scherbatsky in the season one finale, doling out dating advice to Duff’s Sophie.

“If I’ve learned anything at all about love, it’s that timing is everything,” she said at the time. “Sometimes, timing is a bitch.”

In “How I Met Your Mother,” Robin struggled with relationships with Ted and Barney, ultimately marrying, and then divorcing, Barney.

“How I Met Your Mother” ran for nine seasons on CBS from 2005 until 2014.

This article was originally published on TODAY.com