"We all know how you feel about Star Trek's Capt. Picard," Best wrote on a card in the video. "So I searched the galaxy for Patrick Stewart and finally asked his best friend for help!"
"Khalid, I've got bad news for you," McKellen said in the video. "It's good news as well. But the bad news is Patrick Stewart is married. I married him. Well, no, I was the minister at the wedding. He's not available. The good news is that Brett is available. So, think it over. Do the right thing."
McKellen's Broadway credits include the repertory production of Waiting for Godot and No Man's Land, in which he co-starred with Sir Patrick Stewart, The Promise, Amadeus, Ian McKellen: Acting Shakespeare, Wild Honey, Ian McKellen: A Knight Out at the Lyceum and Dance of Death.
The two-time Oscar nominee's film work includes "The Lord of the Rings," "The Hobbit" and "X-Men."
Watch the marriage proposal below.