Dancing With the Stars celebrated its 20th birthday on Tuesday night. The two-hour episode marked the show’s 20-year run, featuring appearances by previous professional dancers, cast members, and champions. The seven remaining contestants each performed a dance inspired by an iconic freestyle routine from a past season.

Six of the final seven also participated in a Relay Dance Challenge that paired celebrities with a returning champion. Whitney Leavitt and Mark Ballas, last week’s top-scoring team, received immunity and didn’t have to participate in the Relay.

For the dance challenge, Alix Earle teamed up with Season 33 winner Joey Graziadei, Robert Irwin was paried with Season 32 winner Xochitl Gomez, Dylan Efron shared the floor with Season 20 winner Rumer Willis, Andy Ritcher danced with Season 29 Winner Kaitlyn Bristowe, Elaine Hendrix teamed up with Season 24 Winner Rashad Jennings, and Jordan Chiles competed with Season 4 Winner Apolo Anton Ohno.

The night was filled with emotional moments, including a powerful tribute to Dancing With the Stars performers who have passed away.

Robert Irwin was only 2 years old when his father, wildlife conservationist Steve Irwin, was killed. Nine years after Steve’s death, his daughter Bindi was a contestant on Dancing With the Stars, eventually being crowned the Season 21 winner.

Bindi’s DWTS run was filled with tribute to her late dad, and her brother, Robert, channeled that for his dance Tuesday night. Robert and his professional partner, Witney Carson, revisited Bindi’s Most Memorable Year dance with her partner, Derek Hough. The pair danced a powerful freestyle dance to Leona Lewis’s “Footprints In The Sand.”

Ahead of his dance Tuesday, Robert teased the performance, saying, “family is everything to me, and I can’t wait for this special night.” He also shared a sweet throwback clip of his dad telling Bindi about Robert’s birth.

When it came time for Robert and Witney to dance, viewers were bracing themselves for the tears that were clearly going to come. During the last moments of the dance, Bindi joined her brother and they held hands as photos of them and their dad were projected onto the dance floor. The moment caused Robert to break down as he was overcome with emotion.

“That was so beautiful. It was a poetic, touching tribute that really touched all of us. I could not take my eyes off of you,” judge Bruno Tonioli said. Carrie Ann Inaba agreed and called the performance “powerful” and “profound.”

Judge Derek Hough was clearly moved as he told Robert, “One thing I loved about your father is that he lived life with so much enthusiasm, and you, my friend, are this generation’s beacon of joy and enthusiasm. And you’re not just walking the path that he set, you are dancing it. And you’re dancing it beautifully.”

This week’s guest judge was DWTS‘s original host, Tom Bergeron, who told Robert, “You know what annoyed me about that dance? I am doing my best not to get choked up tonight, and that didn’t help. Last time we saw each other, you were 11. You have grown into a star, Robert. You really have.”

When it came time to receive their scores, Robert and Witney became the first pair this season to receive perfect 10s across the board.

Watch Robert Irwin’s powerful tribute to his late father in the video below.