The long-running animated series "Family Guy" is coming back for a new season this fall and a popular movie star is slated to make an appearance in one of its episodes.

Sir Ian McKellen is set to guest-star in an episode of the 15th season of "Family Guy." Known for his portrayal of Gandalf in the "Lord of the Rings" trilogy, McKellen will lend his voice to the character of child psychologist Dr. Pritchfield.

When Stewie, voiced by Seth McFarlane, throws a tantrum in school, Pritchfield will be assigned to the boy to see what's wrong with him. With thick British accents, Stewie and Pritchfield's interaction is expected to be a highlight of the upcoming episode.

Executive producer Alec Sulkin shared with Entertainment Weekly, "One of our writers, Gary Janetti, who wrote the episode, also wrote the BBC series 'Vicious' that starred... Sir Ian McKellen."

This strongly suggests how easy it was to convince McKellen to play a part in "Family Guy" despite his busy schedule.

Aside from "Vicious," McKellen's other credits include "X-Men," "X-Men: Days of Future Past," "The Da Vinci Code" and "Beauty and the Beast."

In other related news, "Family Guy" producers dedicated a nine-minute tribute to recently deceased cast member Adam West. The actor who was known for portrayal of "Batman" in the 1960s passed away on June 9 and left behind a long-time character in the "Family Guy" series.

West's role as Mayor Adam West of Quahog was a fan favorite and appeared in over 100 episodes since 2002.

The "Family Guy" crew will show up for a panel at the San Diego Comic-Con on Saturday, July 22 at 1 p.m. PDT/4 p.m. EDT where producers will reveal more details about season 15 as well as their plans for the 300th episode in January 2018.

"Family Guy" season 15 will arrive on Sunday, Oct. 1 at 9 p.m. EDT on FOX.