United Kingdom, Oct. 14 -- Donnie Wahlberg endured a "really difficult year" as he juggled work on his TV show with his New Kids On The Block residency.

The 56-year-old pop star/actor has been busy working on Blue Bloods spin-off Boston Blue while his pop group kicked off a series of shows in Las Vegas in June - and Donnie admits it's been one of the most challenging times of his entire career.

He told The Hollywood Reporter: "I thought I was used to it, but this year was really difficult - far more challenging than any time during my decade and a half doing Blue Bloods while managing my part in New Kids.

"With Blue Bloods, I could walk on set, do my part then focus on New Kids in my dressing room, but now I've added so many hats to my...