The talent show averaged a colossal 13.92m (46.4%) on ITV1 in the 9pm hour, up 900k week-on-week, while a further 998k (3.3%) tuned in on ITV1 HD.
Earlier in the evening, Jimi Mistry's shock exit from Strictly Come Dancing was watched by 10.2m (36.6%) on BBC One from 7.30pm. The programme was followed on BBC One by Antiques Roadshow, which pulled in 5.8m (19.3%).
The First World War From Above secured 2.77m (9.9%) on BBC One in the 9pm hour, but it was soundly beaten by the final episode of Downton Abbey, which brought 9.48m (35.6%) to ITV1 between 9pm and 10.30pm, up 899k week-on-week. A further 460k (1.7%) watched the period drama on ITV1 HD.
Earlier on ITV1, The Cube appealed to 5.43m (20.6%) from 7pm and 243k (0.9%) in HD, but it was outperformed by Countryfile, which brought in a healthy 7.89m (32.3%) on BBC One from 6.30pm.
A repeat of Top Gear entertained 1.85m (6.9%) on BBC Two in the 7pm hour, before Stephen Fry and the Great American Oil Spill had 1.18m (3.9%).
New series James May's Man Lab continued to 1.63m (5.9%) from 9pm, before a repeat of comedy The Trip amused 1.25m (5.2%). Match Of The Day 2 then grabbed 2.75m (20.1%).
Over at Channel 4, The Genius of British Art educated 490k (1.8%) in the 7pm hour and 109k (0.4%) on timeshift. The programme was followed by Undercover Boss USA, which had 790k (2.6%) and 233k (0.8%) on Channel 4 +1.
Secret Millionaire took 2.05m (7.3%) from 9pm and 240k (1.2%) an hour later, before Desperate Housewives entertained 1.17m (5.5%) and 155k (1.4%) on timeshift.
On Channel Five, screenings of The Dirty Dozen, Shallow Hal and Harold & Kumar Get The Munchies attracted respective audiences of 1.13m (4.3%), 1.25m (5.3%) and 418k (5.6%) from 6.15pm.
Overall, ITV1 owned primetime with 33.5% (HD: 1.9%) against BBC One's 19.1%. BBC Two came in third with 6.6%, followed by Channel Five with 4.6% and Channel 4 with 4.2% (+1: 0.7%).
Elsewhere, The Xtra Factor appealed to 1.65m (5.9%) on ITV2 from 9pm, up 520k week-on-week, while 132k (0.6%) tuned in an hour later.
The programme was followed on ITV2 by reality series The Only Way Is Essex, which entertained 713k (2.9%) and 138k (1.1%) on timeshift.
Detective series Thorne: Scaredy Cat pulled in 330k (1.2%) on Sky1 in the 9pm hour.
BARB ratings data supplied by Attentional