Hilary Duff Says the 'Goal' Is to Have All HIMYM Alums Guest on HIMYF After Neil Patrick Harris

Dia Dipasupil/Getty Hilary Duff

Hilary Duff has nothing but respect for a true OG.

The How I Met Your Father actress, 35, is hoping to get all stars of the show's parent series How I Met Your Mother to make guest appearances after Cobie Smulders and Neil Patrick Harris reprised their roles in recent episodes.

"I was really nervous to work with NPH. He's just such a stud. He's legendary," she told Entertainment Tonight on the set of the Hulu spinoff.

RELATED: HIMYF Creators Tease 'Major Impact' Neil Patrick Harris's Return as Barney Will Have on New Series

"Everything he does — if he's hosting something or he's got a TV show on the air or he's doing Broadway — he's just fantastic. And so the fact that he said yes made us really excited," added Duff. "And obviously, our goal is to hopefully collect them all."

She noted that she was the only new cast member to work with Harris, 49, when he made a brief cameo in the recent season 2 premiere. "I took him all for myself," Duff joked.

Patrick Wymore/Hulu

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HIMYF creators Isaac Aptaker and Elizabeth Berger have since teased that Harris will have a "major impact" on the show as he continues to reprise his role as well-dressed womanizer Barney Stinson, whom he played during HIMYM's nine-season run on CBS from 2005 to 2014.

RELATED: Neil Patrick Harris Cameo Teased in How I Met Your Father Season 2 Premiere

"Whenever we talk about bringing back a member of the original crew, you want it to serve two purposes: You want to give some tidbits about what is going on in their lives, where they've landed and where they're at," Aptaker told TVLine. "But it's also about how they impact the How I Met Your Father story, and how they send one of our characters in a new, unexpected direction.

"Similar to Robin last year, we'll learn some more about where Barney's at, but it'll also have a major impact on the trajectory, and main narrative, of our season," he added.

Patrick Wymore/Hulu

Smulders, 40, returned to her role as news anchor and former Canadian teen pop star Robin Scherbatsky for the HIMYF season 1 finale, providing some wisdom for Duff's Sophie.

HIMYM starred Josh Radnor as Ted Mosby, an unlucky-in-love architect who recounts for his two children the story of how he met their eponymous mother. The show also starred Alyson Hannigan, Jason Segel and Bob Saget as future Ted.

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Duff leads the spinoff as Sophie, who goes through her own love story, featuring an ensemble of friends and potential love interests, played by Chris Lowell, Francia Raisa, Suraj Sharma, Tien Tran and Tom Ainsley. Kim Cattrall narrates and stars as future Sophie.

New episodes of HIMYF drop Tuesdays on Hulu.