The Jonas Brothers singer was recently romantically linked with his Smash co-star after they were spotted together on several occasions.
However, he explained that he is "just friends" with the actress and is too busy to date anyone.
"I'm enjoying being a single man here in New York, because my work is my priority these days," he told E! Online.
He most recently dated Australian singer Delta Goodrem for nearly a year before confirming their split in February.
Jonas will return for the first season finale of Smash on May 14.
He is currently starring in Broadway's How To Succeed In Business Without Really Trying.