How I Met Your Mother star Cobie Smulders has confirmed that she will reprise her role of Maria Hill in Joss Whedon's 2015 Marvel Studios sequel, Avengers: Age of Ultron.

"I think I'm in Avengers 2, but it is very top secret," the Canadian actress told the Calgary Herald. "I hope I'm in Avengers 2. I didn't get my invitation yet.

"Well, actually, they know I'm in it but they don't know to what degree I'm in it."

She added: "I am really excited to read the script because they are introducing Quicksilver and the Scarlet Witch into the Avengers universe and the bad guy is going to be very interesting."

The 31-year-old reprised her role as Hill in the first episode of Marvel's Agents of SHIELD, but has said that another appearance is not "on the books".

Cobie Smulders will also appear in 2014's Captain America: The Winter Soldier, while Avengers: Age of Ultron is due for release in May 2015.