United Kingdom, Feb. 26 -- James Marsters has paid a heartfelt tribute to Michelle Trachtenberg.

The 62-year-old actor has hailed his "very talented" former co-star, who passed away on Wednesday (26.02.25), aged 39.

James - who starred alongside the actress on 'Buffy the Vampire Slayer' - told PEOPLE: "My heart is heavy today. We have lost a beautiful soul.

"Michelle was fiercely intelligent, howlingly funny, and a very talented person. She died much too young, and leaves behind scores of people who knew and loved her.

"My heart goes out to her family who are good people, and are suffering the greatest loss anyone could bear. I hope everyone can give them space to heal in this most difficult time.

"Godspeed Michelle. You are missed."...