Visitors to the century-old mansion of William Gillette can expect to enjoy a generous touch of holiday spirit in the weeks ahead.

Volunteers at Gillette Castle State Park and other local organizations have bedecked the interior of the late actor’s eccentric home with yuletide lights and festive cheer and arranged for displays and events.

The decorated castle is open for self-paced tours on Saturdays and Sundays through Dec. 19. Each day’s final tour starts at 4 p.m. Tickets are required to enter the castle, and may be obtained in limited quantity on the grounds or in advance at reserveamerica.com.

The park is open to visitors and visitors may stroll about the grounds during regular hours, 8 a.m. until sunset daily. The external decorations are expected to remain in place through Jan. 2.

One special highlight this year for ticket-holders is a collection of authentic vintage Christmas postcards, on loan from Scott and Shea Jezek of East Haddam. The exhibit may be seen on the castle’s third floor during regular hours.

In addition to providing the display inside the Castle, the park’s Visitors’ Center now is decorated with a life-sized Santa Claus figure loaned by Jezek.

Harold “Tyke” and Theodora “Teddie” Niver also are expected be on hand Sunday afternoons during the holiday season to greet and entertain visitors while portraying William and Helen Gillette.