Nick Jonas says Sophie Turner is the love of his brother Joe Jonas' life.
The DNCE singer and the 'Game of Thrones' star announced their engagement last month and Nick is delighted his sibling has found someone he can spend the rest of his life with, admitting they have a "beautiful" relationship.
He said: "I can tell you that he found his partner and love of his life.
"That's all that matters. It's a beautiful thing."
The pair's engagement news comes just in time for the forthcoming Thanksgiving celebrations, and Nick admitted Sophie has already had a taste of the "Jonas experience".
Speaking to 'Entertainment Tonight', he added: "It's all love. She was with us last year as well, so she already had her first sort of Jonas experience."
But Nick, 25, isn't holding out much hope of being Joe's best man at his wedding because he would feel sorry for their other siblings, Kevin, 30, and Frankie, 17.
When asked if he thinks he might land the role on the big day, Nick told 'Extra': "I don't know; it's up to him to decide. He's got three brothers, so it's kinda rude to pick one.
"I'm so happy for them. She's so lovely and a beautiful addition to our family."
Joe, 28, and Sophie, 21, announced their engagement back in October by posting photos of her ring on Instagram, and Nick later posted the pic on his Instagram complete with words of praise for the pair.
He wrote: "Ahh! Congratulations to my brother... and sister in law to be on your engagement. I love you both so much.(sic)"
Sophie previously admitted she and Joe are trying to keep their romance "private".
She said: "I'm in a relationship, but it's a very private relationship. I'm happier than I've been in a very long time.
"I very much isolated myself for a while and forgot what was fun. Going out with friends, going out to eat, not really having a care. And people I've met recently in my life have drawn me out of that.
"It really helps you own those insecurities. The things I tortured myself about before, I can forget about."