Ian Ogilvie, 50, and Allan Donnelly, 47, preyed on the teenager for months - even filming the abuse.
Ogilvie was already on the sex offenders list for life at the time - and was also the subject of a supposedly strict order banning him from going near under-16s. The pair were caught after a man allegedly asked to take part in the abuse alerted police.
Ogilvie and Donnelly admitted a string of sex charges at the High Court in Glasgow. A judge said both took part in a "deeply horrifying level of depravity".
The victim had moved to Scotland around six years ago from Thailand.
Donnelly started having sex with the youngster when she was 15 at his home in Airdrie, North Lanarkshire.
Last June, he introduced her to Ogilvie - who was already on the sex offenders register after being caught with child pornography. He and Donnelly abused the girl together, often at Ogilvie's home in Motherwell.
Judge Lord Pentland called for a risk assessment on the pair before sentencing in October.