The GRAMMY-winning singer and sports agent have been dating since 2021.
In a clip, the "Hello" singer is seen looking into the crowd before she says, "I love you more than life itself, we wish you a happy birthday," before going into the song.
After singing to her love, with some help from the crowd, Adele giggles and proceeds with her concert.
Paul, 41, marked his birthday on Dec. 16.
In August, the "I Drink Wine" singer gushed about her boyfriend, whom she has been dating since 2021.
"I've never been in love like this," she told Elle about the sports agent. "I'm obsessed with him."
While she is madly in love, at the time, Adele confirmed that she was not engaged and was just wearing a large piece of jewelry that she really liked -- and it happened to be on that finger. When joking about the rumors, the star added that she "might as well be married," due to how in love she is.
In addition, Adele shared that she wants to expand her family.
"I definitely want more kids," the mother of one said. "I'm a homemaker and I’m a matriarch, and a stable life helps me with my music. But right now, all I got in my brain is Vegas." She added, "I wanna f**king nail it."
Adele was previously married to Simon Konecki, with whom she shares a 9-year-old son, Angelo.
In July, the GRAMMY-winning singer opened up in a separate interview about how Paul has influenced her to come out of her shell.
"I think now that the relationship that I’m in, he’s like, 'If you want to go to that restaurant, you should go and try the food at that restaurant, and if you want to go to this birthday party, then you should be going. You can’t miss out on these things, what’s the worst that could happen?'" she said during an appearance on BBC Sounds' Desert Island Discs.
Adele and Paul went Instagram official with their love in September 2021. Since then, the pair has had cozy courtside date nights and even attended a friend's wedding, alongside LeBron James and his wife, Savannah.