Dancing with the Stars contestant Brian Austin Green celebrated his son's birthday with his girlfriend and pro dance partner, Sharna Burgess. The couple made their first appearance as dance partners in the season 30 premiere of DWTS, marking the first time Sharna has danced with a significant other. Despite being a 14-year veteran at DWTS and taking home the Mirrorball Trophy in season 27, dancing with the former Beverly Hills, 90210 star is new for her. According to Sharna, the biggest challenge for her and Brian, who she's been dating for almost a year now, is learning how to approach dancing together each day. Luckily, there haven't been any rough moments in rehearsals thanks to the pair's good communication skills.

Brian's ex Vanessa Marcil, with whom he shares son Kassius, cheered him on in a supportive Instagram post. While Brian and Vanessa haven't had the most amicable relationship in the past, with Vanessa claiming Brian was not a part of their son's life and that she never loved him, things seemed to have changed. Vanessa posted a photo of Kassius on social media with a caption saying he's on his way to see his dad, hashtagged in support of Brian. This seems to show Vanessa's support for Brian's DWTS journey, in which he earned a 24 out of 40 on his first dance.

Related: DWTS: Sharna Burgess & Brian Austin Green's Dating Timeline

Sharna took to her Instagram Story to talk about celebrating Brian and Megan Fox's son Noah's 9th birthday. "We had an awesome birthday party yesterday," Sharna said in the video while Brian drove (via Us Weekly). Brian noted that while they had fun at the party, he's "going to suck on Monday," when he and Sharna have to dance the rumba to "Say You Won’t Let Go” by James Arthur. At least the pictures they took in the party's photo booth came out good, according to Sharna.

Brian & Sharna first dance on DWTS

Brian also revealed that the theme of his son's party was Titanic since Noah is obsessed with it. Aside from Noah, Brian also shares kids Bodhi and Journey with Megan, who he was married to for about 10 years.  "The kids had an amazing time. We had an awesome time with the photos too, and Noah had a great time, which is the best," Sharna said. "So it was beautiful and it was worth it, but we have some catch-up to do today [with the dance routine]." From what Sharna said, it seems like she has a good relationship with Brian's children, as well.

It's nice for fans of both Brian and Sharna to see them celebrating his son's birthday together, even if it has an impact on his next dance performance. Dancing with the Stars doesn't usually pair up couples, so it will be interesting to see how their relationship influences their dance partnership over the course of the season. Even if Brian and Sharna don't take home the coveted Mirrorball Trophy at the end of the season, it will still be a fun watch for fans.

Next: DWTS: Sharna Burgess Reveals Stricter COVID-19 Protocols For Season 30

Dancing with the Stars airs Mondays at 8pm EST on ABC.

Sources: Us Weekly, Sharna Burgess/Instagram