Evans Vestal Ward/NBCU Photo Bank via Getty
Derek stopped by The Ellen DeGeneres Show on Friday and said staying at home with his girlfriend Hayley Erbert brought the couple even closer together.
"We came together, we got closer," he said. "We grew as a couple tremendously. We even started a YouTube channel together, cooking."
When asked if Derek, 35, feels ready for marriage and kid, the Dancing with the Stars judge played coy.
"Maybe," he teased, joking that if his and Erbert's YouTube channel hit "half a million subscribers" he'd consider it.
Derek and Erbert first began dating in 2015 after meeting on DWTS, where she began as a dancer in Season 21.
The couple was self-isolating together at home in Los Angeles, but Derek has since returned to work on the hit dance competition show, taking on a new role as a judge alongside Carrie Ann Inaba and Bruno Tonioli. (Hough last appeared on the show as a pro during season 23.)
But while Derek and Erbert's relationship flourished during quarantine, his sister Julianne Hough separated from her husband Brooks Laich amid the pandemic.
Julianne and Laich confirmed to PEOPLE in May that they had separated after three years of marriage.
Getty images (2) Brooks Laich, Julianne Hough
"Brooks really still wants to make it work and she's considering it but taking her time. He's open to whatever it will take," said the source, adding that Hough also still feels positively for her ex.
"Julianne likes the idea of freedom but doesn't want to lose such a good, solid guy," said the source. "Everyone who knows him knows how grounded and great he is. Her friends and family don't want her to lose someone like that."
Season 29 of DWTS airs Monday nights at 8 p.m. ET on ABC.