‘TOM'S NOT YOUR DAD!'

Katie’s criticism of her ex strains the once-tight bond between mother and daughter...

You only turn 13 once. Which is why Katie Holmes went all-out for her daughter Suri Cruise’s milestone birthday in mid-April, flying the teen and two pals to Paris to celebrate.

“They had the best time ever,” a source tells of the girls’ getaway. So jell!

But those close to Katie say the festivities took a solemn turn when the star decided it was time for Suri to finally know the truth about who she really is...

“She sat Suri down and confirmed what everyone has known – but hasn’t acknowledged – for a while now... that Tom [Cruise] will never be a real father to her,” the insider claims.

There’s always been hope that the actor, who’s kept a painful distance from Suri since he and Katie ended their five-year-marriage in 2012, would have a change of heart and embrace his daughter once again. But now that Suri is older and mature enough, the source says, Katie, 40, wanted to address the issue head-on.