Jussie Smollett's timing to enter rehab is peculiar ... at least according to the Osundairo brothers, whose testimony was critical in convincing a jury to convict him.
Abimbola "Bola" and Olabinjo "Ola" Osundairo tell TMZ ... if Jussie really had a problem that required treatment from rehab, he could've checked himself in a long time ago ... but he waited until an appeals court was ready to rule on his conviction for faking a hate crime.
Ola and Bola believe Jussie realizes his chances of having the conviction overturned are remote, and he may be trying to create sympathy so he serves time under house arrest and not in jail.
Jussie appears to be in rehab for substance abuse other than alcohol. He was spotted Monday with a fresh haircut ... clutching a "Narcotics Anonymous" book.
Bola had previously admitted he scored Jussie drugs but denied he ever sold them to the actor.
Regardless, the bros are hoping Jussie gets the help he needs ... but Bola adds, "Truth will set him free."
As we reported, Jussie was sentenced to 150 days in jail after being found guilty of lying to police about an alleged attack by 2 Trump supporters in 2019 -- he was released shortly after he began serving his sentence, pending the appeal.
Since then, he's been spotted working on set in California and even hanging out with his former "Empire" costar Taraji P. Henson.
But, Jussie's rep told us the past few years have been extremely difficult for him ... and he has quietly been working on himself in an outpatient program.