Sophia Bush honored her late ex-boyfriend, Dan Fredinburg, on what would have been his 34th birthday on Wednesday.

The 33-year-old "Chicago P.D." actress was left shattered after learning that Fredinburg, a former Google executive, was killed during a massive earthquake in Nepal while climbing Mount Everest. Although still lost for words, Bush took time to share a sweet message in Fredinburg's honor on her Instagram account.

"I still don't know what the words are. Magic. Friendship. Memories. Consciousness. Dimensions. Infinite. Break. Dance. Live. Believe. Do," she wrote alongside a photo of blazing lights.

"So many. None are the one. They're puzzle pieces but not the whole picture. What I do know is that you are missed. That you are still here. That you changed us, inspired us, pushed us, and guided us. What I do know is that I saw you this weekend, deep in the desert, many times."

Bush and Fredinburg dated for 10 months before splitting in August 2014, after which they remained close. In her post, the former "One Tree Hill" star decided to share her memories from her visit to the Burning Man festival in the Black Rock Desert in Nevada over the weekend.

"I saw a man in spandex & a Viking hat, near the ashes of the wooden man that burned on the playa the night before. I turned to the Minion gals, pointing, & said 'hey Viking I see you!' & pulled up to the man to take a photo of the back of his hat, under the giant bird-shaped cloud that had followed us around all day."

"His friend noticed me & said, 'he'll kiss you if you ask him,' and I laughed and thanked him, but passed, explaining that I just wanted to take a photo of his hat. The friend said, 'Hey Dan, this girl wants to take a pic of your hat!' 'Of course your name is Dan,' I said, & he turned toward me on his bike, which of course had a Minion toy strapped to the front of it. The girls and I all laughed aloud, got misty-eyed, & turned to go, knowing you'd been saying hello."

Bush and her pals shared stories, screamed his name to the sky and left photos and prayer flags in his memory, writing, "We screamed 'I love you!!' as it burned & a chorus of 'I love yous' began echoing among the tens of thousands of people watching, bouncing all over the playa as it had when I once stood watching that structure burn with you & someone else screamed the same thing for someone who had most likely meant to them what you mean to us."

Us Weekly reported that Fredinburg was a fan of Burning Man. This week, Fredinburg's family and friends shared a photos and stories of him, considering Wednesday "#LiveDanDay15."

"So today, on your birthday, our first #LiveDanDay, I'll say it again. I love you my friend," Bush concluded her post. "I'm grateful for every memory. I'm grateful that we had a friendship that defied context, & a connection that defies physical boundaries even now. Your squad reps you hard, dear one. We live bigger because of you. We will keep writing your name in the sand & dancing in the dust to honor it. To all of you out there who need a little inspiring, take it from Dan. Live big."