The CMA Awards will air live from Nashville, Tennessee, on Wednesday at 8 p.m. Eastern on ABC.
Stapleton is nominated for album of the year, male vocalist and new artist of the year.
Timberlake, who is from Memphis, Tennessee, has been a supporter of Stapleton since before his solo debut album, Traveller, came out earlier this year. Stapleton has written hits for Luke Bryan and Kenny Chesney. He was lead singer for the bluegrass band The SteelDrivers.