Singer Robin Thicke appears to be on a mission to win back his estranged wife, "Mission Impossible" actress Paula Patton.

During a concert Sunday night in Atlantic City, N.J., Thicke broke into his slow song "Lost Without You" and Al Green's classic "Let's Stay Together." They were direct messages to Patton, who is the mother of his 3-year-old son, Julian, People magazine's Raha Lewis said.

Robin Thicke Dedicates Song to Paula Patton After Split

"Someone yelled out, 'I love Paula,' and he said, 'I do, too,'" Lewis said. "Right after that he started singing Al Green's 'Let's Stay Together,' which was quite romantic."

The performance on Sunday at the Borgata Hotel Casino & Spa Event Center followed another appeal at a concert in Virginia on Thursday, Thicke's first since the high school sweethearts announced their split.

"I want everybody here to know that I'm trying to get my girl back," the singer, 36, told the audience, before breaking into his 2007 hit song, "Lost Without You." He says he wrote the song for Patton.

The two announced last month they were separating after eight years of marriage.

READ: Paula Patton and Robin Thicke Separate

While Thicke was singing for Patton on Sunday, she was at the Academy Awards after-party thrown by Vanity Fair magazine, reportedly not wearing her ring.

(Photo Credit: Chad Buchanan/Getty Images)